I've got one that I like. I had a T-Rex Alberta and a Visual Sound Route 66 that I liked better. But those have been gone for a while now. The MXR seems noisier and a little less full-sounding then those pedals were.
Anyways... I usually use my comps for when I desire to do the Brad Paisley "maximum squish" deal for country leads, or something slightly less for jazz shredding. I usually just prefer to use an OD (usually my OCD) to hit an amp that's already "hairy" for rock leads.
I've used it as an od boost on nmv Marshalls, but prefer using an old Electro Harmonix LPB2. For Cleans-- and solo boosts w/ clean tones the MXR Dyna Comp is my FAV.
love me some Dyna Comp! I have an older pre LED one I use for cleans and it's one of those pedals that once you have it on you don't want to turn it off