Thought I'd share my experience with 5 different options I've tried with the KPA for those of you (like me) obsess about available options!
First, I didn't use an FRFR at all - I used two 1x12 cabs powered by a 50 watt Mesa Boogie tube power amp. I turned the cab sims off, of course. I played 6 gigs like this, and I liked it just fine. The reason I went this way is because I have QSC 1x12" powered speakers for my P.A. and didn't like the sound of the Kemper into it (in fact, I mic'd the 1x12's instead). I felt that the P.A. speaker sounded too "fake", not warm like a real amp.
As soon as the Friedman ASM-12 came out, I thought I'd give it a try because of their reputation for good products. From the minute I plugged it in, I said "Holy crapola - where have you been all my life?" The sound was very real, very huge, and the different cabs had a distinctly different sounds. When I raked the strings, the speaker would "pump air" so to speak, like a real amp does. Did my first gig with it on a low speaker stand about chest level, with the lunchbox KPA on top. It sounded very loud to me being right behind me at that height, but the bandmates said it was a perfect volume and sounded awesome.
I thought I was done, but my obsessive-compulsive nature (ya'll know what I mean) drove me to try other speakers, because the Friedman is HUGE and 54 lbs.
Next I tried the Matrix Q12. What a disappointment! It was small and light for sure, but sounded boxy, small and for the price was a complete ripoff. Consider that the Friedman is cheaper and sounds 10x better. The Matrix went on the chopping block in about 1 hour.
Next up, I thought I'd just get a small backup/portable speaker for short gigs where I can just "grab and go". I got the Laney IRTX, which is about 25 lbs. and under $400. Not bad at all at low volumes, but crank it up, and it loses the nice fidelity present in the Friedman. Of course, I didn't expect it to sound as big, but for $375, it's a good bedroom speaker or backup you can keep in your trunk if your main speaker blows up.
Finally, after much searching, I found an Atomic CLR cabinet (not the wedge, the full cab). Paid $900. This one was almost identical in bottom end and "bigness" as the Friedman at first. But when you crank it up a lot, the high end gets a bit "ice-picky", but then again, I don't think I'll be running it that loud onstage if I mic it. What's nice about the Atomic is that it has different settings for different placements (on the floor, tilted, or on a stand). I have a tilt back stand, so it was perfect. Then, I tried it with both left/right outs to the two inputs of the Atomic and it REALLY shined because I didn't have to crank it up as much (thus no issue with the ice pick). On the form factor, it's much more like a real amp, 1/3 smaller than the Friedman, and about 8 lbs lighter. Easier to carry too, because of the handle placement on top (the Friedman has a side handle which makes it difficult to lug)
So, my first gig with the Atomic is tonight, and I'll give my final opinion tomorrow. But it's damn close in tone.