I used to have the FD version of the 35/2.0. It was one of my favorites. I suspect it's been updated.
It is a great lens, in all of its versions. The only drawback is that it isn't a 1.4, which is now made for Canon bodies. It is your fastest choice for FD, however. If you don't need to use f/1.4, this won't really affect you. If you feel that you need an f/1.4 lens, you can adapt a Nikon 35mm f/1.4, but if you don't need it, I doubt you will have any problems with the Canon one. Also, they are very cheap. Sometimes they will even come on a body.
In response to David, Canon also has an EF 35mm f2.0, and it is fine optically, but is of a really crummy build quality and has no USM.
P.S. I earlier posted that the FDn and EF models might be optically similar, but I just checked the specs, and they appear quite different. I did not find cross sectional diagrams, but I did find that the FDn is 10 elements in 8 groups with 8 diaphragm blades, and the EF is 7 elements in 5 groups with 5 diaphragm blades.