I got an Axe Fx Ultra about a month ago and I just played my first show with it a few days ago so I though I would post what I thought so far.
I also snagged a Digital Music Corp. Ground Control V2 on ebay (I have really wide feet and nothing else I have found works quite as well for me.)
I had to sell practically everything that wasn't nailed down to swing the Ultra but I must say it was worth every penny. The amp models are unreal and the effects are mind blowing. I'm running the Axe with the power amp sims on with no thump through the 2:90 into a rectifier oversized 4X12. The tone is fantastic. The learning curve is pretty steep so it definitely took me a while to figure out how to program it but the Axe Edit program is an absolute must if your going to tweak this thing.
Right now, my lead tone is a modified factory preset of a mesa mark 2 with a little delay and I'm pretty happy with it. My main heavy rhythm tone is a modified rectifier preset and it's pretty good but I'm looking forward to digging deeper into the amp models and coming up with something more original.
The Axe Fx has really streamlined my gear needs. My bands rehearses direct through headphones with an electronic drum kit, plays live amplified through real amps and an acoustic kit, and records direct. Before I bought the Axe Fx, I had different rigs for each of these situations. It's so nice having one rig to handle everything.
Now I just need to purchase an expression pedal that works with the Axe Fx.
I've played two gigs with the Axe-FX Ultra since I bought it. The setup I do is using the instrument outputs to the amp/cabinet for monitoring on stage then line-level outputs to the PA for everything else.
The only problem was that we were told afterwards that my guitar tone sounded amazing, but overwhelmed the other guitarist (since his amp was miced for both monitors and the PA). Of course, his amp wasn't doing too well that day, so there was that as well, I guess.
When I used the GNX3000, I used the on-board wah-wah, but with the Axe-FX Ultra, I use my old VOX wah-wah, which I had forgot how much I love to death. That wah-wah is the ultimate. The god of wah-wah pedals.