AWESOME! This little green heart-shaped box is more versatile than you could even imagine.
The compression itself is wonderful, it kills dynamics a little (hey, this is a compressor, and compressors mainly work by KILLING dynamics), but at least it doesn't kill your tone unless you turn the effect knob all the way up.
But the marvel of this box is that u can just back off the compression knob and play with the level knob to use it as a boost, just like a tubescreamer (but at 1/3 the price)... I've used it that way and the results were wonderful! The tone stays always good, I mean it does color your guitar's sound a little bit, but not in a bad way (at least for my musical tastes).
Actually I'm using it wih my backup rig which consists of
REXX 602 solid state preamp
Marshall Valvestate 8008 solid state poweramp
Marshall 1922 2x12 cab
I actually use it to add that tubey feeling to the preamp's clean channel, but in the past I've used it to give a boost to my Mesa/Boogie V-Twin pedal preamp's Lead channel and it was a blast!
It comes in a plastic case, which ain't encouraging, and other reviews I've read on Danelectro pedals added doubts to doubts.
I haven't gigged this pedal yet, nor I'm planning to do it because I already have a compressor in my main rig (Mesa TriAxis->TC Electronic G-major->Mesa 20/20) and the TriAxis really doesn't need a boost(!), anyway I think I'd buy another one as a backup if I ended up gigging it (at that price u can really afford it!).
To be sincere I've had it for one year and it hasn't failed on me yet.
Some stuff works great regardless of what music style you are playing, and this is one.
Anyway I play Melodic Rock (a la Scorpions/White Lion) and some Dream Theater sounding Prog stuff.
This is a good effect, it is actually capable of two different works: the compressor and the booster, always with a wonderful tone.
I really suggest anybody to try one, you'd be impressed!