I usually play a Gibson SG through a Carvin X-100 tube combo amp. I wouldn't say I'm trying to get anybody else's sound in particular, but I need access to good distortion, compression, phase, chorus and delay most often. I have pretty much abandoned the distortions on this unit in favor of just overdriving my amp, although I think that shreddy metal types might find a few things in here to make them happy. As I mentioned, I've also ditched the cab simulations, since I found it just too frustrating to get a handle on EQ and fix things on the fly in the Korg rather than just twiddling the Carvin's tone knobs, and I'm not really looking for a wide range of cab sims for live performance. The compressor is passable, although I think it might be the source of some noise in my effects chain. Phase is very good, delay and looping are reasonably versatile (except I wouldn't trust the sample-and-play for a live gig since the switch under the expression pedal is a bit dodgy), wah sucks. It's disappointing that certain effects can't be used together, like chorus and flange, for instance. A lot of the more off-the-wall effect options are nifty in theory, but pretty useless in practice.
I've been gigging with it without a backup, but I'm headed away from that for two reasons: (1) The wall-wart's cable keeps coming out of the clip that's meant to hold it in place, which means it's getting stretched from use, and it now only works in one power strip that I have to carry around, and even then it only works in one direction. If I accidentally kick the power strip, the unit powers off and on. (I've ordered a replacement.) Some online specs I've found seem to suggest that the unit also takes batteries, but it doesn't. (2) The unit may be susceptible to extreme heat. I played one outdoor gig in midsummer where the display started flashing like a strobe, the bank selector would only move in reverse, and it kept skipping the banks where my most frequently used patches were; I wound up having to manually set up my sounds between songs. It never happened again after that day, but that sketched me out. On the plus side, the chassis is extremely durable, and I haven't had anything else on it physically break.
I guess I mostly play art-pop these days with overtones of prog, blues and 70's dinosaur metal; been playing for over two decades. I'm going at least partially back to stomp boxes, since they're so damned satisfyingly tactile and modular, but I plan to keep this unit in the chain at least for now for the delays/loops, the tuner, the phase and maybe a handful of other options. The unit's bypass is non-polluting enough that I think I can do this without inflicting serious damage on the overall sound.