I demo's all three k8, k10 and k12 yesterday at GC in North Dallas. At the store, I used my Rick Turner RS6 electro acoustic guitar, which is very balanced and I know the sound very well. All eq/voice settings on the monitors were set flat. If you audition these at GC, make sure you set them flat. Also, I really don't think you can audition these type monitors with playing recorded music through them. You need to use an instrument you know well. Started with the k10. It was very balanced, good tight low end, punchy when I wanted it to be. Very impressed first try. Moved to the k12. The k12 was not as balanced to my ears and had a "box" or tubby sound over the k10. Did not care for the k12. The k8 was balanced but sounded smaller than the k10. The k10 seemed ideal. Brought the k10 home and plugged the axefx in. Big, even sound. It can get window shaking loud too. Very happy. I also mix music and have Barefoot mm27 monitors to mix on. I previously dialed in my axefx presets using the Barefoot monitors. The presets translated well to the k10. More surprising was that I dialed in presets with the k10 and then checked them on the Barefoot monitors. The presets stayed true to what I got on the k10. The presets I use are a Fender Deluxe clean setup, a Marshall ish overdrive setup (acdc type), an acoustic preset for my RS6. All 3 worked great. I play in two bands. One band we have 4 Bose L2's. The other just a standard PA/sub setup. I will check to see how the k10 translates to the Bose later this week. With the other band (large 20+ people), I will use it at rehearsals and as a floor monitor since it is designed to lay back like a monitor also. Great size, weight and sound. Love it so far.
Stay tuned, my opinion may change as I get more mileage on it.