Sanderxpander
I don't think that's entirely accurate, L3 is a multiband peak limiter.

well,
the fact that it's called a 'Limiter', and not a 'compressor', is a leading fact.
 

I'll use MB (maul the band) if the material calls for it. Usually it's a problems in the source mix itself.
Otherwise I'll leave it off, I never start off with one.
I also prefer using min phase because of pre-ringing issues with linear.

just because you have 5 bands to work with,
doesn't mean you can't just focus on ONE band.......
and bypass all the rest!
 
just an idea for you to play with......
 

I have used the LP64 Multiband on just about ever project I've exported for a few years now. If set properly it does an excellent job of catching the odd over. And because it does this seperatly for the five bands there is never any audible damage done,,,"that I can hear" ,,, 
It also lets me know what band is too hot so I can go back and re mix or EQ at the track level. 
My goal is that it just tickles the meters every so often. If one of the bands shows steady downward your screwing up,, that will cause damage. 
I set a super fast attack and I pull them down a touch from the preset possition. The lowest one I pull right to the center line. 
Anyhow all my mixes are usually bang on fequency wise so I must be doing something right. It's not first class but it's as good as I'm going to be and it was free. 
 
I also master in wave lab but LP on the master has saved me extra work and generally no further EQ processing is required in Wave LAb, just top and tail and RMS leveling. 

I use the Fab Filter MB. It has a linear phase mode for Mastering. Also, Ozone 6.
Not that I've done that much Mastering yet, but those are what I use.

I don't compress the master bus at all, myself. I have a whole lot of buses downstream that I do compress: a drum bus with some light compression, a parallel bus with drums and bass with heavy compression, maybe a bus for all guitars as a group that may or may not have compression.
 
In all of those cases, I've never used anything as fancy as a multi-band compressor.
 
 

Mastering as a separate step is another matter. I multi-band that stuff all over the place. But during mix, I like to have the master bus doing nothing other than summing.
 
It's a definite skill, mixing into master bus compression, and some great mixers swear by it. But it's one I don't have, and find so counter-intuitive, I expect I never will.

I should add I only use the MB for some live stereo recordings, so basically having to mix and master at the same time.  The MB is perfect for this task.  My first stab at it came from a live recording that wasn't too bad - I used an Olympus LS-14, and ended up with 2 main problems. The first was some bass resonance around 110 Hz that was quite boomy, and the second was that the guitar (this was mostly instrumental ska and reggae featuring a lot of solo guitar) got lost in the mix quite a bit. There was a horn section that was the main culprit there.  I was able to fix both problems quite nicely with the MB.  The bass was very easy since it centered around a tight frequency range - set and forget basically.  The guitar took a little more effort since the volume and range changed quite a bit but I was still able to bring it forward in the mix nicely like it needed.

I'm not a mastering expert at all so take what I say with a gran on salt.
 
If you think you need a multi-band compressor on the main out, ask yourself what is it you are wanting to compress. Since you have the full project available it may be better to correct the mix.
 
Once you have the mix the way you want it then start compressing as needed. I sometimes have leveling compressors on tracks like the bass or a vocal. Then I mix to taste and usually put a smile shaped eq on the master just before a limiter. Then crank the limiter till I think its good.
 
For me I have found that if I'm trying to correct lots of stuff in the main output bus then I have a problem somewhere in the mix that needs sorted out.
 
YMMV

batsbrew

Sanderxpander
I don't think that's entirely accurate, L3 is a multiband peak limiter.

well,
the fact that it's called a 'Limiter', and not a 'compressor', is a leading fact.
 

You are right, of course, but your post could be interpreted as if it wasn't multiband, aka a traditional brickwall limiter. Or at least I read it that way and wanted to clarify.