Kemper's built in poweramp is VERY GOOD.
So if you want a top notch all in one solution go for it.
BUT: It is mono. If you need to go stereo for your poweramp you should go for a 3rd party solution.
I use to own a Matrix GT800 when I had an Axe2
i absolutely love my Kemper Powerhead, I prefer using guitar cabs fwiw
The main reason for me to buy a power rack was the weight (just 1 kg extra for the built-in power amp). I don't really need the power of 600 W, but an additional weight of 4,5 kg for an amp like the Rocktron Velocity 100 LTD in my rack is just too much for my back 
An cheaper power-amp solution for the head-version is the camplifier:
If you can go for the powered Kemper, do so. It's a little more expensive, but an aftermarket solution won't (1) be as elegant, (2) be cheap either. Of course, there is the new Ambrosi Amp module, which could swing your boat.
For me, the issue came when I was ready to move away from a guitar cab to using an FRFR speaker. I couldn't find any recommendations for really good passive speakers and ended up trying and using a Yamaha DXR10. It is fantastic, but I could have saved the money on the Powerhead and bought the non-powered version. That said, if in the future, if for some reason there were an issue with the DXR10 or some fantastic passive speakers come on the market or appear before me, I have all my options covered?
Cheers,
Andy
I've lately been using an Atomic CLR wedge which I like for the tribute band in which I perform as the only guitarist. However, I've started rehearsing with a two-guitar band, and the other guitarist has a traditional head/cab setup which my CLR just doesn't compete with as a backline amp.
Really? That's hard to imagine for me unless the other guitarist is loud beyond sensibility, damaging not his own ears but also those of his bandmates.
I've lately been using an Atomic CLR wedge which I like for the tribute band in which I perform as the only guitarist. However, I've started rehearsing with a two-guitar band, and the other guitarist has a traditional head/cab setup which my CLR just doesn't compete with as a backline amp. Therefore I want the flexibility of a powered solution.
In a crowded rehearsal room, or onstage? How are his cabinets arranged, and your CLRs?
It's not about volume. It's about sound spread and bass response. One speaker just can't push air like two. No matter how I EQ myself in the room I just get lost.
Don't let Jay Mitchell hear this. 
(Maybe he reads this?)
TBH my experience is quite the opposite. Nothing beats the dispersion of a CLR. And the bass response is just fine.
I really wonder what's the culprit here because the CLR should be superior to any guitar cab in this regard, be it 1x12", 2x12" or 4x12".
In a crowded rehearsal room, or onstage? How are his cabinets arranged, and your CLRs?
OK, so obviously I'm talking about in-the-room sound here, not FOH or anything like that.
The other guitarist has a Cornford MK50 head placed on a Marshall 2x12 cab. At practice, I tried my CLR in every position.. On a pole, on the floor, on a box. The other guy's rig always had more "girth" than mine, even after I EQ'd in more mids, bass, etc. I just couldn't get it to sit right. We play Alice In Chains/Soundgarden stuff.
Maybe this is less of a CLR issue and more of an Axe-FX issue.... ? 
I've lately been using an Atomic CLR wedge which I like for the tribute band in which I perform as the only guitarist. However, I've started rehearsing with a two-guitar band, and the other guitarist has a traditional head/cab setup which my CLR just doesn't compete with as a backline amp. Therefore I want the flexibility of a powered solution.
This is what troubles me and constantly has me re-thinking what I want to purchase. This does but in the same line doesn't help my decision.
Maybe this is less of a CLR issue and more of an Axe-FX issue.... ?
Given your tonal issues over the years, one would have to conclude that you are very unlikely to be satisfied with any modeler through any amplification or speakers. Whatever your problems may be, they cannot be solved by gear purchases.
