One more reason for F3 over red.
The F3 will have more lens options soon. When Sony offers the zooms, for probably a lot less than many alternatives, it will really be nice. You can use PL's of course or Sony mounts with no trouble or ordering and fitting of aftermarket mounts and both will be considered stock, factory mounts.
The Epic should be ok but you still have the same red sensor and the horrible form factor of a DSLR which will keep up the vibrating handheld shots for a long time to come.
You can use just about lens any RED, and it is probably just as simple or hard to do. You can choose the easy, cheap, good triangle, the same for any other camera with a lens mounting system just about. Save Nikon.
And, after having been outside about an hour and a half ago with a half decked out Epic shooting and getting used to the camera, I can definitely say that the form factor is not an issue, and neither will handheld vibrations etc like DSLRs.
In fact, I'm going to go out on a limb and say once someone figures out the Bomb EVF and LCD mounting system, it's going to be a pretty well received setup by a good heap. It's definitely gotten me to realize I need to get the battery and drive off of the RED MX and into a backpack.
I think all of these cameras have great form factors now. Not too light and not too large and heavy.