I've been very pleased with mine, which I got only about two weeks ago with a Control 2. I'm running 4cm with my Pittbull UL, and I've found some very usable modeling in there since I haven't had a chance (yet) to pick up a midi switcher so that I can do channel switching on my amp through the Control 2. I'm running 5 switch, 5 effects (stompbox style) right now. I upgraded to the C63 mustbebeta update. The modelers I use a bit are the 68 Jump Panel, the Triple Rectifier, and the Orange OR sim. Right now, I just have 5 patches: one is my amp with switchable boost, whammy, delay, and lex hall reverb. The second is the Orange OR120(? or is it 100, I can't remember), third is the Triple Rec, 4th is a Fender Twin for cleans, and the 5th is a boosted Jump Panel with delay and reverb for ballad style leads.
When I run through my amp, the sound is pretty convincing. In a band mix, I still tend to gravitate towards my Pittbull preamps for distorted sounds when I want to cut, but for rhythm hard rock, the Triple Rec gets a lot of burn, and I'm using the Twin modeler for my go-to cleans. Rehearsals have been really nice on my ears, too. My bassist is going direct from his SansAmp, and the other guitarist has a sound shield in front of his miked Mesa Maverick. We've got the drums miked also, and I'm running from the XLR (Cab sim) out of my GSP1101 with my Pittbull's power section on mute. The result is very low volume in the room, and sound clarity with all of us having control over our mixes, including a click track. As we prep for recording an album, this is pretty awesome (and we've been recording our rehearsals with ease). As a band, we are actually getting better as a result of this set up, and having very passable cab simulation makes it possible. Otherwise, to get any type of decent tone with my UL, I'd have to crank it a bit to a) compete with bleed from my drummer and b) get it to sound nice.
The downsides (granted, I haven't used X-Edit, so my patches have been made straight on the GSP
Only one mod effect available at one time. I may pick up an old Quadraverb to integrate in with this for this very reason. Second is expression pedal control assignment. I still don't get how to assign the whammy to this, and don't know how the Control switch works. Third is some of the choices for effects in certain blocks. I wish there was an independent pitch block so that I could, say, run, a whammy through a phaser, etc. I also like to get really chaotic sounds, and this potential seems limited with the GSP. I'll need to tune my noise gates a bit also.
All told, though this is my first foray into modeling, and it's been surprisingly pleasant. Considering I got the GSP1101 and Control 2 for $430 including shipping, I'm pretty happy. Very low noise, which was a big selling point. That said, I'm still going to be running my Whammy 4, POG, and maybe even a phaser in front of my board depending on what I end up going with as far as a Quadraverb or something like that.
Also, WAY less tap dancing.
