The three big differences I see are shutter type, lens coating, barrel design, and flare supression.
C - older, Compur shutter with limited or no lens coating.
CT* - same as above with multicoated lens.
CF - same as CT* but with Prontor shutter and redesigned barrel (more rigid).
CFi - same as CF but upgraded Prontor shutter (lasts roughly twice as long) and better flare suppression due to better internal barrel coatings
CFe - same as CFi but with electronic contacts for use with 200 series.
There is a lot of talk about the CFi/e having a cheaper feel but I think this is nonsense. Both are excellent. The flare suppression on the CFi/e matters for longer focal length lenses in high key situations -- i.e., where there is a lot of white background in or just outside of the picture. The upgraded Prontor shutter only matters for professionals taking 1,000's of pictures -- the CF can handle roughly 200K exposures; the CFi/e about 400K. Both are a lot.
Multicoating matters more as contrast will be enhanced under most circumstances as opposed to high key circumstances. But, higher contrast isn't always necessary -- in b/w you can adjust for higher contrast through developing and/or printing. With color this is more difficult. In general higher contrast is better.
What has been said about Hasselblad lenses in other fora is that for quality one should focus on the lens design rather than the age of the lens. I agree. The 100 for ex&le is better than the 80 and the perspective close enough to make them equivalent except for studio use where you may not be able to step back far enough.
Anyone serious about purchasing any lens, and in this case a Hasselblad V-system lens, should become literate in reading MTF and distortion graphs. These are available from Hasselblad and Zeiss. Although not the whole story, these graphs will tell you much about the performance of the lens in absolute terms and relative to other lenses. It is surprising in fact how little information is not captured by these graphs -- chromatic errors being one of them.
Of course, the nature of medium format is that a mediocre lens on the bigger 6x6 negative will equal or better a good lens on a 35mm negative. Moreover, excellent technique -- a sturdy tripod, mirror lock-up, an adjusted camera back for a flat, true film plane -- will sw& differences between lenses. So, give a great photographer a C lens and you will see stunning images. A well-designed CFi/e in the hands of a mediocre photographer -- not much to talk about.