My setup is pretty simple: a Kramer Focus 1000 guitar (modified: EMG 81 humbucker at the bridge, another EMG SC at the neck), Hughes & Kettner CS-100 solid state power amp (100 W, 19", 1 HE, half width), 2 Hughes & Kettner 4x12" cabinets.
The built-in noise gate combined with the expander gives good results. I cannot complein about too much noise at all! ;-) The effects section is great. As others mentioned there are plenty of opportunities and I really don't use the full palette of the SGX. There are different complexities of reverbs: from very simple and obvious ones to some diffuse high quality ones that sound pretty realistic. The same applies for most other environmental effects.
I'm playing Heavy Metal, better kind of Thrash Metal and I like having high gain distortion without loosing the clarity of the sound. I can tell you that it's not that easy to get a metal-like sound from the unit. You have to set the distortion level to max and tweak the sound heavily with the EQ, the acoustic environment simulator etc. After all I succeeded in getting a sound that's good for our music. But there's not much room for playing with the settings. For high gain you're approaching the limits of the SGX. You have to balance distortion, grumble, and noise very sensitively! If you're looking for a flexible sound generator this unit is for YOU! You wanna play top 40 stuff or to cover Pop, Rock, Heavy (not ultra high gain)? Then this is fine. There are even factory sounds that let you sound like famous guitarists. Just by selecting the pattern. That's really great. But be warned if you wanna get a sound that's somehow extreme...
My impression is that when I installed the "Express" upgrade I got a bit more distortion...
Wow, you shouldn't have asked for this one... ;-)
After a year the 9V outlet on the back didn't work anymore. It has been disabled with the Express upgrade so I assume they had some global problems with this one. After 2 years one photo sensor of the X-15 (MIDI board) gave up. It had to be repaired. This photo sensor is required for the expression pedals of the MIDI board.
Recently the unit started to produce awful feedback. When I stop playing the amp doesn't! :-( I asked the support and they confirmed my impression that this sounds like a valve problem. Since I carry the unit very often I guess the valve is stressed pretty much. This can cause microphony after a while. I replaced the valve and the problem still existed. The I found out that I had to disable the loop circuits to stop this effect. I was happy since last week when it started again. I don't know whether another repair is worthwhile... I don't know what to do if this happens during/before a gig...
For my music style (Thrash Metal) it seems not to be the best match. For people who need to have a broad palette of sounds and flexibility it's a pretty good choice! You won't miss any effect or parameter here! I've used it for about 10 years now and during that time I reduced my needs for effects pretty dramatically that I think I'd like to have a pure sound with a pure preamp. It's just too much possibilities if you stick to your style. I love the way you can edit parameters, I dislike the damn long time it needs to switch to a different sound. That's really ugly. When I had to change a sound immediately I assigned the critical parameters to one of the expression controllers on the X-15 board. This way I was able to fade one sound into the other quickly. I wish it would have more gain. That's the most important problem I faced.