what rack multi-fx to get?

The G-major doesn't have a wah, unfortunately, at least IIRC.

I really love(d) my Digitech GSP1101 - great wah, reverb, chorus, delays, surprisingly good pitch shifting and harmonization, and was easy as hell to set up. The only reason I don't use it anymore is because I bought an AxeFX.
 
Yeah, the XPression fucking rules in terms of quality of effects and is built rock-solid (the same can't be said of the G-Major, apparently :erk: ) - but yeah, no switching relays, just MIDI in/thru
 
thx for the answers so far, which one does affect the amp sound the least? I tried a boss gt-8 with the 4-cable-method and it sounded like shit.

Well the XPression lets you totally bypass the A/D conversion (and of course assign that as a MIDI-switchable patch), thus eliminating any tone-sucking potential (though I didn't find it to suck tone really at all when I had it! Though I never gigged with it, sadly, so maybe at high volumes it's different)
 
After much deliberation and asking around, I am going with the Boss GT Pro. A couple people have complained about it with the 4 cable method kills tone..... but plenty have said it doesn't so I am just going to find out for my damn self.

Plan on ordering mine with the Roland FC300 as soon as my amp/rack case is finished being made for my Uberschall.