Got to test out all four of these at the same time. I invited all SF Bay Area Kemper-ers to come but only one showed up! Maybe he will give his opinions as well. I can try to answer any questions, but everything is packed up and ready to ship out so I won't be plugging them in anymore. The Matrix I bought used so if anyone is interested in buying it, PM me.
Atomic CLR Neo Mk II
Yamaha DXR10
Matrix FR12
Mission Gemini GM1-BT
Right down to it, the Atomic is the undisputed champion in my eyes...er...ears. Sounds so crisp from whisper quiet to knock you over decibel levels. It does everything well from vintage Fender Twin to double triple quadruple rectifier chuga chuga. I mostly use quality studio monitors to refine my profiles and I find I need to change very little when playing through the Atomic. The only question is if it is worth more than double the price of some of the others?
The Yamaha can certainly shine just as well as the Atomic with a few tweakings or switching the DSP settings on the rear. Under low volumes it really has a tendency to sound boomy. Offset that by switching the DSP to the monitor setting and the boominess is gone, but you still have to tweak a bit if you dial in your profiles using studio monitors like I do. And it is LOUD. The DXR10 is definitely the best bang for the buck, but I'm keeping the Atomic.
The Matrix FR12 is the one I wanted to like the most. The weight of this thing, or should I say, lack thereof is amazing. My 6 year old could probably carry it and roadie for me. But, it really sounded thin at low volumes. You really need to turn it up to get the lows and mids to where they need to be and it actually does come close to the clarity you get from the Atomic. The Matrix has 3 DSP settings but the effect is negligible to my ears and didn't compensate enough for my low volume issues. If I were a regular giggin' kinda guy, I could see myself using this exclusively at rehearsals and gigs for the weight and convenience alone. But, for a bedroom poser like me, it just wouldn't get much use.
The Gemini is the one I am having the hardest time parting with. Like the Matrix, it is pretty anemic at low volumes but sounds better and better as the volume goes up. The Gemini has one advantage, a dial where you can lessen the high frequency driver, which helps a bit at bedroom levels. Or, completely turn it off and just use the 12” EV speaker (and turn off cab IRs). What I like most about the Gemini is that it absolutely feels like a real cab when you turn it up. It does change the sound though, but just like a real cab, it's in a good way. You get warmth and richness from the real birch that you don't get from other FRFRs. The reason I'm not keeping it because, like the Matrix, I just won't be using it at the levels needed. But, wow, this really sounded like a real cab when cranked. If you're having trouble liking FRFR, try this one.