I just picked up a Canon EF (FD lens mount.) I had never heard of one of these until recently, although I have used a Canon A-1 since 1991. I sought out an EF for its voltage regulated power supply, mirror lockup, copal shutter (125 flash sync) and light meter which works with f1.2 lenses. I found a FL 55mm f1.2 a while back for $25! and found the A-1 unable to meter properly with it wide open. The EF is shutter priority, but since both aperture and shutter speed are indicated in the view finder, it reminds me more of EOS 630 program shift with FD lenses.
I am waiting on a light seal kit, but shooting a roll anyway cause I can't wait. The EF is my most expensive 35mm SLR at ~$50 shipped. I got it from http://www.kenmorecamera.com/ it was in better shape than I thought it would be from their ratings. They are usually outa my price range on e-Auction and I felt better getting one from a dealer.
This camera has renewed my interest is shooting my Canon FD lenses. Nikon FE goes on shelf for a while.