I've been through a bunch, don't use them often, but finally settled on an AnalogMan BiComp. The old Keeley 2-knob is good as is the old as in 70s MXR Dyna Comp and most things based on an 1176, like the MXR M76 or the Boss CP-1X, among others. Boss CS-2 and Ibanez CP-9 were on my board for a number of years.
I've got three ways I use them. For the squishy stuff, I like the Orange Squeezer side, not that the Ross side can't do that since the Ross Compressor is based on the Dyna Comp. However, I used the Ross side with the sustain turned way down, almost off, and use the level as a boost. It's not a clean boost, but it's not an overdrive, either, and I like what it does for leads. The third way is in the loop and more as a limiter. For that, I've got a dbx 160a.