Ian has a point about the weight and size. The 1.4 is quite large in the barrel department, but that is offset by the silky smooth focusing capability, and I mean silky smooth like a hot knife in butter. At the same time focus doesn't shift, unless you move it.
I use mine mainly on F3 bodies, if I'm going to be using one for a really extended period of time, I'll put the motor drive on. I know this adds even more weight, but the balance factor is perfect.
Plus with a drive added your left hand is lower down and therefore the focusing ring grip falls perfectly into your lower palm and fingers.
Without a drive added the camera cannot sit flat on a bench with the lens attached, it sits facing upwards a bit. Meaning that without a drive your left hand is bent down slightly and I do know that this is a slightly awkward position to maintain for a few hours. Personal experience with that one.
When my FE2 motor drive worked, I nearly always attached the drive when using the 85 1.4 for this very balance reason.
I still wouldn't consider the 1.8 anywhere near the capabilities and razor sharpness of the 1.4 version though. If you are doing colour then you will be pleasantly surprised with the 1.4, it is a wonderful performer with colour film.
I would suggest the 85 f2 is possibly better than the 85 f1.8. The f2 version is earlier than the 1.4 I have and was manufactured in the late seventies through to the introduction in the early eighties of the 1.4 version.
The f1.8 version is a later version manufactured after the 1.4 and as far as I know is only available as an auto-focus unit. At least the 1.8 versions I have seen and used were auto-focus units, not particularly great on a manual focus camera, but certainly usable.
Mick.