I LOVE the compressors that Yamaha built into the Software for the THRs (found in the Editor Section).
The Stomp Box one is Great, but the Rack Mount one is truly exceptional. If you haven't yet found this, I really urge you to hunt it down and spend a little time with getting to know it.
Because of the rebirth of my Slide thing, Compression suddenly starts to matter again and this Rack Mount Comp is an absolute Joy!!
Apparently, it is the same one as their Top End Studio version and it, alone, makes a THR worth every penny it costs.