Ya keep cm7. Its totally worth keeping especially if you keep up with the nightlies. And even if you dont, get nightly 10, and then check back in a week. Nightly 10 is super stable and it kills sooo many bugs.
it will fix your camera and the mms problem in some of the newer builds\
I love liberty so much, and until Cyanogen is fully stable I understand why users would want to stick with it. as soo is there is a release candidate there is no reason not to. CM7 on the DX is a HUUUUUGE accomplishment