Mike Curtis from HD for Indies has a good article on the newly announced RED Scarlet. And it’s pros and cons. It is well worth a read.
It does seem that the Scarlet is the better deal here, though the process is harder to shoot with, but the results should be better.
The Canon lenses issue is the same with both Cameras, and could actually be solved with the new Canon EF Cine lenses they are releasing with the EOS C3800.
I still think both cameras are a bit too expensive, and the Scarlet will have beta issues as it is s RED.