G-Major is a very good effects rack. I own one. I previously used a Quadraverb Plus (1989). It had a warmer sound and a built in EQ, but no tuner. It also had different options not geared specifically for guitar. The G-Major has very decent effects, tuner, comp, and funtionality at a very good price - and it is made for guitar
I use a Tech 21-NYC MIDI Mouse foot controller. No A/C - just a 9-Volt. Very simple yet effective. I recommend both highly.
I did, however, expect the G-Major to have an EQ, Harmonizer and an Auto-Wah, or at least I haven't found them yet.
I use a Mesa Formula PRE Preamp, DBX para EQ rack, Furman Power supply rack, Mesa Stereo 2:Fifty Poweramp - double rack space (all weighs a ton of tone). I run it all in stereo and the G-Major is great for that. Because it is 24 bit I don't use the Mesa effects loops, I just run the stereo signal through the unit and into the poweramp. The Quadraverb is 16 bit and I could have experienced tone problems, so I used the effects loop to get around this. No longer the case. The sound is crisp and biting, but the all-tube Mesa preamp and poweramp still provide fantastic tone.
The G-Major's flangers, chorus, phasers, delays, reverbs, comps, pitch shift, tremelo all sound great and give you different types of each to select and configure.
I use the old Quadraverb with my Yamaha P-80 and get some really great 'Coldplay' keyboard sounds with it.
TC G-Major - very good rack, great price. As Chris Milne suggested to me - be careful with the knobs and buttons. He broke them twice, I haven't. Maybe his was an earlier release because I, so far have been lucky.
Good luck to you!!