I've been testing and demoing a few compressors by Waves, specifically the DBX 160, the API 2500, the CLA-76, and the SSL Bus Comp.  I don't like buying things I don't really need (easier said than done), and I usually try to check something new against what I already have.  My DAW-world is essentially Ableton Live 10 Suite now, with some older projects still residing in the SPLAT realm, just waiting--and begging--to be released from the prison.  So no more Sonitus compressor (still one of my favorites) or ProChannels for me!  But it got me thinking...in testing the Waves demos, I should do a comparison to some older Cake comps as well.  Without further ado, I give you my non-scientific comparisons!  Let me know what you think, and if I'm way off the mark on this garbage/waste of time.  Thanks!
 
(Oh, I should mention that the tests were performed in Live and SPLAT, A/B'ed and level-matched against an inverted signal so only the differences are heard.)
 
Cakewalk/Sonitus Compressor: Oldie but still a very good compressor!  Wish I could still use it in Ableton Live but it's DX. Very very transparent, with no distortion or artifacts. Quite smooth!
 
Cakewalk ProChannel PC76: Kind of hard to dial-in, IMO. Crunchy. Compression seems weak compared to the Waves CLA-76, however it does add a little punch. Definitely not as good as the CLA-76…not even close.
 
Cakewalk ProChannel PC4K S-Type Bus Comp: Compression seems extremely weak compared to Cytomic’s the Glue, Live’s Glue compressor, or any other compressor for that matter. Attack times don’t seem to jive with expected results. Maybe a slight bit of punch added, but this is nowhere near as good as the Waves SSL Bus Comp.
 
Ableton Live’s Compressor: Absolutely transparent, no distortion, no artifacts, and very, very smooth.
 
Ableton Live’s Glue Compressor: Relatively smooth on attack and release with some very light crunch/artifacts on the knee.  This compressor behaves much differently than the bus compressor it’s supposed to imitate, the SSL master bus compressor.  This comp just is a crunchier and pumpier version of the above compressor.
 
Cytomic the Glue: Behaves and sounds 99% the same as Live's Glue compressor, which makes sense considering it should, in fact, be the same compressor.
 

Cakewalk CA-2A: Pulses, and it seems to let through HMF frequencies easier, hence its preference on vocals.  Add light crunchiness and light coloration on the knee.
 
Waves H-Comp: Absolutely NOT transparent, with heavy distortion and heavy coloration like it’s being over-driven despite conservative settings and analog mode turned off. Thinking about selling off this compressor!
 
PSP MixPressor2: Not sure what this plugin does other than deepen the low frequencies and heavily distort the sound. It’s basically sounds like the MixSaturator2 with a weak-ass dynamics section.  Hearing what this plugin does (or doesn't do) just bolsters my opinion of PSP: they kinda suck.
 
Fabfilter Pro-C2: Not as clean and transparent as I thought this compressor should be. Crunch/artifacts on the knee, progressively increasing on “Clean, Classic, and Opto” modes. “Vocal” mode behaves like the CA-2A. “Mastering” is very smooth and transparent. “Bus” has light crunch and faster-firing on the attack.  “Punch” is hard to dial-in, but “Pumping” is smooth and sounds good.
 
iZotope Alloy 2: Light crunch on the attack, but not overly transparent due to it not being very smooth on the release.  Thought this compressor would be more transparent.
 
Beat Skillz MAX-1: This was a freebie.  Sounds like it acts more like a gate than a compressor. Terrible!
 
Melda MCompressor: Relatively smooth on attack and release with some light crunch/artifacts.
 

Variety of Sound Density mkIII: Can adjust punchiness by tweaking the “color” screw. This compressor can sound punchy, but can get harsh when the Timing knob is on P1 or P2. Adjusting the “Strict/Relax” screw helps a little bit, but the compressor definitely sounds better with slower timing, i.e. P3 to P6. I think this would make adjusting the compressor pretty difficult in the mix.
 
Waves SSL Bus Comp: Relatively smooth on attack and release with some very light crunch/artifacts.  This compressor behaves quite differently than the Glue compressor.  Actually, it’s better despite all “the Glue” hype on KVR and GS. The Waves SSL Bus Comp let’s more “thwack” through, and I can hear how it could make mixes, drums, and basses more punchier and have that “sought-after” sound.  If this is supposed to replicate a real SSL console's bus comp, then it all makes sense.  I never heard what the SSL bus comp is supposed to sound like until I demoed this plugin.
 
Waves API 2500: Hard to describe this one. It has some deep, beefier crunch, making sounds and frequencies come through and punch out, especially with the feed-forward (new) mode. The Tone section is definitely where this compressor shines. Character definitely happens in the “Med” and “Loud” modes. This compressor is pretty sweet.  Maybe on the wish list for this one. I can get similar results with FF Pro-C2 and some careful EQ'ing, but this wastes time.
 
Waves CLA-76 (Blacky Mode): Punchy and smooth. Moving the release knob adds rhythmic vibe, with the compressor riding the kick drum and creating a wave-like effect. Increasing the release knob increases punchiness/pumping.  This compressor lives up to the "1176 hype" and sounds like it can definitely make drums pump. The “all buttons-in” mode pulses/limits heavily but still sounds good and musical despite more crunchiness.  I'd definitely consider buying this plugin.
 
Waves CLA-76 (Bluey Mode): The same operation as above, but brighter than “Blacky” mode.
 
Waves dbx 160: Smooth on the attack and pop.  Let’s drums/sounds punch through without harshness. One of the best parts of this compressor version is the mix knobs, making it a great parallel processor. This is a very punchy compressor.  This one is also on my wish list.
 

2:43AM
Hearing what this plugin does (or doesn't do) just bolsters my opinion of PSP: they kinda suck.

I can't say I agree with your opinion on PSP. I've got the Xenon limiter, Master Comp, PSP 85 delay, and 2445 and Springbox reverbs. I've always found their plugins to be of great quality. Maybe Mixpressor2 is an exception, but I don't think it's fair to say that PSP sucks. I do appreciate the thread, though.

Leadfoot

2:43AM
Hearing what this plugin does (or doesn't do) just bolsters my opinion of PSP: they kinda suck.

I can't say I agree with your opinion on PSP. I've got the Xenon limiter, Master Comp, PSP 85 delay, and 2445 and Springbox reverbs. I've always found their plugins to be of great quality. Maybe Mixpressor2 is an exception, but I don't think it's fair to say that PSP sucks. I do appreciate the thread, though.

Thanks for the post! I don't have any of those plugins as I only own the MixPack2 set. I mainly bought the pack for MixSaturator2, which seems to unfortunately fall into the same category of "What's Going On Here?"  I've invert-tested it as well, but I'm left scratching my head. Take the following as an example of what I mean. MixSaturator2 has mainly two modes of saturation: "Valve" and "Tape." There is a third, "Digital," but it doesn't do anything (ha!). Now, with valve (aka tube) saturation, using a 1kHz tone, I'd expect even harmonics (2k, 3k, 4k, 5k...). Likewise, with tape saturation I'd expect odd harmonics (3k, 5k, 7k...).  Proving this theory, both Alloy 2's exciter, Ozone 6's exciter, and Fabfilter Saturn all replicate this flawlessly, with some adding more "character" into the mix.  PSP MixSaturator2, however, does not. It doesn't matter if you select Valve1-2-3 or Tape1-2-3. They all produce the same result, just with varying loudness.  Both tape and valve settings produce odd harmonics.

That's weird... I don't have the Mixpack2 set. I'll definitely take your word for the results though, as you have obviously tested it thoroughly. I guess I can only speak for the plugins I have. I like them a lot, and have gotten great results with them. Based on your test results with the MixPack2 set, I can see why you have a negative opinion of PSP. I do know that Lexicon approved their recreation of the PCM 42 delay, with an endorsement from the original designer himself. I wouldn't completely count them out. They offer demos of every plugin they make. Maybe give some of the others a chance.

By the way, I'm in complete agreement with you on the Waves API 2500 and dbx 160 comps. Awesome...

Leadfoot
That's weird... I don't have the Mixpack2 set. I'll definitely take your word for the results though, as you have obviously tested it thoroughly. I guess I can only speak for the plugins I have. I like them a lot, and have gotten great results with them. Based on your test results with the MixPack2 set, I can see why you have a negative opinion of PSP. I do know that Lexicon approved their recreation of the PCM 42 delay, with an endorsement from the original designer himself. I wouldn't completely count them out. They offer demos of every plugin they make. Maybe give some of the others a chance.

You should try the demo of MixSaturator2 and let me know what you think! You can't demo just one, but a demo is available for all the MixPack2 plugins. I don't know...I like a tool to state its obvious purpose, then live up to said purpose with results that confirm the purpose. A fine example, for me anyway, is the SSL Bus Comp vs. the Glue vs. PC4KS. I've always read about the greatness of the SSL consoles, the greatness and hype associated with the bus comp, as well as the fiddle-faddle from the Bakers about the ProChannel module. In the past, I performed countless tests with the PC4KS, trying to understand it.  Trying to understand how awesome it should be. But I never heard it. Even "the Glue" is so freakin' hyped up, it's ridiculous...but it isn't anything that jumped out and impressed me. I was happy to get it native within Live 9.  But basically, as the name implies, it's just a smooth, gluey comp.  Fast forward until now and for some reason, I never demoed the Waves SSL Collection.  Holy crap, it's what I was supposed to be hearing!  It's what an SSL Bus Comp (albeit a plugin) is supposed to sound like.  I'm definitely not a Waves fanboy, but damn!  The SSL Bus Comp was easy to adjust (though the +/- Threshold knob is weird), it lived up to the hype, and it provided easy-to-hear results.  I wasn't left struggling to hear what it's supposed to do, wasting hours on end in headphones and straining to hear the difference(s) in the monitors.
 

Leadfoot
By the way, I'm in complete agreement with you on the Waves API 2500 and dbx 160 comps. Awesome...

 
Yeah, these are going to be hard to resist!

Yeah, I never understood what people saw in the PC4KS either, or the PC76, for that matter. I do like the CA-2A, though. I agree that the Waves SSL Bus Comp is the nicest sounding SSL emulation I've heard.

Have ya'll demo'd the bx_console E from Plugin Alliance? That one sounds pretty good too. 
 
Tony, I also had never tried the SSL. I mean I played with it and looked at it, but never really gave it a go until recently. I have a project and placed a Waves SSL on every track and started from scratch with the mix. When I finished a rough mix of the drums I knew this was something different. The drums just had a sound that I can only describe as focused. And moving from trk to trk was very easy. Much much easier than I had ever expected it to be. I was able to just click the plugin and see the same UI and just go! It all came so naturally.
 
Anyway, I did the same project the same way with the bx_console E. Started from scratch and worked from there. Got great results with this plugin too. Same thing. Ease of use. Great UI. Just a much more focused sound than what I was use to.
 
I have to give it to Waves, their SSL plugin is easier on the CPU than the bx version. I do like the layout of the bx version a little better. But both sound extremely good.
 
BTW I was working with the E version in both the Waves and the bx. Have not put the G versions to the tests yet. Nor have I gave the N version of the bx_console a go yet.
 
And to be fair, I have in the past used nothing but the included plugins and console emulations that come with SPlat for mixes to see what they can do. They are not bad by any means.  And you could do good work with them alone. 
 
But color me a SSL man from now on!!