A key part of the question is whether you have any urgency. Are you unhappy with the k10, or do you just want to have the best thing out there? Is there any deadline to return the k10, or is it yours at this point?
If you have no urgency, I'd wait for the matrix wedge and atomic clr to come out and get a shootout against the RCF.
But to anyone who needs or wants something right now, get the RCF. That was my situation, and I am thrilled I did. It's the best thing available right now in that price range, and should hold up well against the others whenever they come.
I can't compare it to the k10, but I did not like the k12 at all when I tried it. I found it harsh and brittle sounding. The RCF is orders of magnitude better, in my opinion.