[raymo]

I've never had an f/4, but everything I've heard suggests that they are harder to collimate, and more sensitive to miscollimation, and harder to focus accurately. Actually, the physics of optics points to those things being right.
The SW coma corrector necessary for imaging with the f/5 is much cheaper
than the one for the f/4 scope.
The EQ6R is definitely superior to the NEQ6, if only for its belt drive which
hugely reduces drive train backlash, which should give better guiding.
The more secure power connection is also a plus. Using a 6 over the 5
will also allow you to go up a scope size in the future.
If your budget allows the EQ6R, I would opt for that and the 200mm f/5
and the SW f/5 coma corrector. If you need to save $500 or so, the NEQ6
will do a perfectly adequate job.
Having said all that, if you are certain that the 200mm is as big as you
will ever want to go, the HEQ5 will carry it easily, and is quite a lot lighter, and $500 cheaper than the NEQ6. I don't know whether this will help or confuse you.
You will need a coma corrector for imaging with the f/5, but you don't have to fiddle with spacing if you get SWs f/5 coma corrector, just fit it and use it.
raymo