I got a great deal on both of these at a pawn shop the other day. I think I like the Mercury a little better but both are cool. Is anyone else into these?
I have the mercury edition. It's a great amp IMO and it is very easy to dial in. Sounds great with any of my 4x12 cabs. If you haven't yet, I recommend that you hook it up to a 2 button footswitch with a TRS cable and use one of the alternate switching modes so you can access all 4-channel. You will lose the ability to footswitch the reverb, but you can use outboard FX with it with add a better reverb anyways.
I've had both, still have the Mercury. They kind of meet in the middle sonically, but I find the Mercury the more versatile of the two boxes. (That said, it depends on your style a bit.)
If you get the "Midi1" adapter then you can use MIDI to change a bunch of other parameters that are handy.