However, I have heard some negative comments regarding the in-built poweramp of the Kemper; is it possible to bypass it if I wish to use a 3rd party poweramp?
Don't believe every BS that people on the interwebz throw at you.
The built in Kemper poweramp is a top - class product made originally by Bang & Olufsen.
I like the ability to be able to turn the power amp on or off or take the cable out if I want to with the Ambrosi.
I don't know about the powered rack I'm afraid....
Have a look at Cost and Use mainly because in a rack your are less likely to be bringing it home from every gig anyway ....If you are gonna bring it home every night ( which you WILL want to do ) then the head is the way to go I think. Very portable , very light ( even with the Ambrosi section in , dont know about the Kemper power section ) ....
just my opinion from my experience 
For some weird reason I agree with what Rob wrote 
No, the other way round!
Send -15db to FOH and unlink Main Outs from the volume knob. @Robman: this will solve your problem.
Eep. Yes, that way.
I received my Camlifier 290 at the beginning of the week. I'm using it with an Avatar stereo 2x12 w/ Celestion G12K-100. They are a fairly neutral speaker with good bass reproduction. I have to say that I am really happy. Room shakingly loud when needed. It's a heavy metal wet dream. I was using a pair of Yamaha DXR8 before. The 2x12 cuts through on stage a lot more, so is much easier to hear with the band. I'm really impressed with the fit and build of the Camplifier.
For some weird reason I agree with what Rob wrote
Now Don't get used to it GF 
!
... OK ...
I received my Camlifier 290 at the beginning of the week. I'm using it with an Avatar stereo 2x12 w/ Celestion G12K-100. They are a fairly neutral speaker with good bass reproduction. I have to say that I am really happy. Room shakingly loud when needed. It's a heavy metal wet dream. I was using a pair of Yamaha DXR8 before. The 2x12 cuts through on stage a lot more, so is much easier to hear with the band. I'm really impressed with the fit and build of the Camplifier.
I am waiting for my Camplifier 290 to get here. Hoping next week! I will be sure to post my thoughts.
My Ambrosi ATM-70 is on it's way as we speak... In the next couple of weeks I hope to make a short video with a drummer to show the volume.
I received my Camplifier 290 today . This thing is awesome!!! Easy to install and rocks loud. Sounds amazing! I am so glad I went with this one. I run it thru a Randall RV412 that is loaded with x pattern of Vintage 30s and G12 T-75s. I am a metal rhythm player. So I am running profiles like that of SinMix producer pack. Turn off the cab emulation and get blown away. This is definitely worth the money. Thanks to Tillman and Kemper staff for all the information leading up to my purchase. This is one bad ass combination!! \m/
My Ambrosi ATM-70 is on it's way as we speak... In the next couple of weeks I hope to make a short video with a drummer to show the volume.
I hope you guys will both be wearing ear protection !!!!
Got my Camplifier 290 yesterday. Extremely well built and rock solid.
I tried it yesterday during a rehearsal with our band (very LOUD drummer): with the output set at a 1/3rd, allt the other guys were complaining that I had been way too loud
