Reviews on Center tell you it's not a necessity.

Where did you see the reviews, KVR? Also makes you wonder how many others are not necessary...

 I don't remember but I read them after I bought it. 

Bummer dude :)
And I just missed the introductory price...

I guess you may try to ask Craig Anderton how to replace those two Waves plugins with Sonar stock plugins/effect chains and you will save some real money.

revnice1
 
I'm always tempted because they sound like a quick way to do remarkable things but surely you should be able to mix and master without such things?

I suggest if you get 7-10 days trials for plug-ins.
I also used to be tempted to buy plugins - but seeing a video plugin cannot be judged fully - this is my opinion. All plug-ins are not fit for all types of songs.
Moreover, this cannot be just one magic-wand.
 
If I am tempted to buy a plug-in -
I wait for 3-7 days - this normally brings down the temptation and gives time for rational thinking.
I try to identify what the plug in is doing which my existing plug ins are not being able to do.
I have a list of plug ins - vsti effects I have purchased. I give a glance how many of them I haven't used  for long, or forgot, or started not liking them.
 
I clears my mind and let me decide better.
 
Regards
Snehankur.

revnice1
Digi:
>Just have Waves put you on their email list, and, every so often, a discounted plug comes up.
Yeah, but what do you think of them? 

Leaving aside the "signature" ranges, to my ears Waves plugins range from "that sounds really good" to "nope" via "useful in the right place at the right time". Which is pretty much like the offerings from most plugin developers. Some of the most generally useful are the kind of thing like Cakewalk already provide in tools like the excellent Channel Tools. You don't need them very often but when you do you're grateful. InPhase (and the LT version) is one such, DeBreath can come in handy. The Waves C6 multi-band compressor likewise if you want to do something complicated with side-chaining.

Some of the more "effect" type plugs are good. I like Waves' exciters, Doubler is good on the right material though sometimes a simple chorus effect does better, the REDD and T12345 consoles are fun if you like a truly old-fashioned feel sometimes. ReelADT provides instant 1960s Beatles/Small Faces/through-zero flanging.

Waves reverbs and delays are in the "don't bother" class, Cakewalk's CA-2A comp is better than the Waves version I think, and the ProChannel compressors are Waves's equals. For a different but excellent (if you like what it does) comp+eq BozDigital's 10+dB is at least as good as anything Waves makes.

Given what comes with Sonar Plat, the Waves stuff I'd personally go for are the oddball effects like ReelADT and T12345. Most of the other stuff you can do with Sonar's plugs pretty well unless you want a different tone-colour - often subtly different - rather than "something that's the same just better". Much of Waves's range really fills in gaps in what the various DAW makers provide. SonarPlat has very few gaps. I've found myself learning Logic Pro over the last 8 months or so and I was surprised at how much better SonarPlat's plugin range is than most of what comes with Logic.

Waves once upon a time had a reputation as the "top of the tree" plugin house and prices to match, rather like ProTools HD. The world has moved on since then. You really need to install trial versions of a few things and see what you make of them.

You know, not to beat a dead horse, but I've heard tons and tons of compressors and eq's and the two best I've heard are the UA stuff and ....if you can believe it the...the liquid mix emulations.  If you're up for an adventure I'd try to get my hands on an old liquid mix, maybe just for fun.  Only drawback is you have to use jbridge.

I have a few Waves plugins that I use all the time. The Aphex Aural Exciter is one of them as well as Bass Rider. I've also been using the H series compressor and delay in my guitar chain and I like what I hear. They carry a few unique processors that I haven't seen anywhere else and the quality is very good in my opinion. Once again, if it makes you happy and inspires great music, it's a win.

For 30 bucks I think Center is useful if you find yourselves working with stereo wav mixfiles a lot.
 
I have a rather large bundle of them (Horizon)  though I haven't WUPed. I don't use all of them but there are plenty I really do like and some I would really miss if I didn't have them:
Renaissance Vox often works magic for me. I'm aure I could dial in a CA2A and PC76 chain with some gating for a similar result but most of the time RVox just nails it in practically no time. I think I use it in virtually every project. Vocal Rider and Bass Rider are useful and time savers too. The Renaissance DeEsser and EQ are also good although I mostly use my FabFilter alternatives. I actually really like H Delay and sometimes SuperTap although the Sonitus Delay and one of the BlueTubes are pretty good too. I agree the Cakewalk CA2A is better or at least better to me than the Waves one. I would really like CLA bass which I don't have yet, I've used it and it was great. And I still find lots of use for IR1/L with its sizable library of spaces.
MondoMod and S1 stereo imager are useful too. And I've used Doppler more often than I'd have thought beforehand. 
 
It still seems quite popular to hate them, I don't think that's fair. Maybe it's because they've gotten a bit gimmicky with all their artist plugs. 
The things I like least from them are their emulations of hardware, but apart from ampsims I'm not a big fan of those anyway. Their utility plugs are really useful and something like RVox is still relevant after ten years and is still used lots of times on commercial records.