I've had my Kemper PowerRack for a while for home use and last night decided to use it at a gig.
My usual rig is PRS Custom 24 through Drop - Tuner - Overdrive - Wah - Phaser into a MESA Dual Recto or Diezel Einstein with Delay in the loop into a Marshall or Genz-Benz 2x12.
Last night it was just PRS into Kemper into 2x12. So compact, so light, so quick and easy to set up!
I wasn't going through the PA, just through the cab, and it worked brilliantly. My main worry had been the posts about people struggling to get enough volume in live situations or destroying their cab. No problem there! We play rock/metal (Hendrix, Floyd, Metallica, Megadeth, Alice in Chains, Sabbath, etc) and have a reputation for being a LOUD live band and the Kemper coped admirably.
Several people commented on how good my sound was, better than the MESA or Diezel!
Any issues? Well the switches on the remote are a little bit too close together for my liking so I had to be careful when making quick changes on the fly. In the live situation the Kemper phaser didn't sound as good as my trusty MXR Phase 90, but that will just need some tweaked parameters I guess. Worst problem was when I accidentally switched the looper on mid-song and, never having used it before, didn't know how to stop it - that was rather embarrassing! This morning, thanks to this forum, I've seen that you can disable the looper switch so I've done that ready for next time.
Apart from that it was an excellent gig. I had two other guitarists come up afterwards and ask what amp I was using, no-one could believe so many great sounds can come out of such a small light box. I'm now seriously thinking about selling off lots of gear that will be gathering dust from now on!