If Im honest I made a bit of a fuss about how when i got rid of my comp it sounded absoloutely no different and therefore wasn't needed and it was all a bit of snake oil etc. But it's quietly made a reappearance on my pedal board, I'm not sure why but I think it's when we play some really quiet phrases during the set I missed having control over the dynamics, and the comp provides just that, more control over the peaks, as you say it doesn't really alter the sound at all so it's not an effect as such but it makes playing during the set just that bit easier.