I thought the point of using a compressor was to compress the dynamic range of sounds. IE squash the sound then use the gain to bring it back up to where it was before, so the quieter sounds sound louder in the mix without making the louder sounds peak or distort, I know you can also use compression to change the tone of sounds, but to increase volume as a whole, im not so sure, I think eq's and the mixer do a better job of that. And a limiter/maximizer, like you say it is just a compressor on max, that is to get the most volume out of a final mix without peaks. Thats what I use it for anyway. I think using eq's on every channel has a better result than using compression.
I can get my drums to bang and leave headroom for a bassline pretty easily by just using eq's. And only using compression on the overall mixdown.