alum
I like the alum frame everything is well positioned, everything fits without pushing and shoving and preloading like my 04 rm. As an intermediate vet mxer I cant feel a quantifiable difference in stiffness between the cr and rm, but I do like the balance of the cr better. Most contribe this to the frame. I think it just fits me better. It has been through alot of abuse with no problems. and no rust to worry about. I know I know alum corrodes. blah blah,,,,I would worry more about the motor of your next bike than the frame though. No one I know has broken any part of a cr falumi frame, but several friends have broken steel frames, pegs, linkage mounts etc....