Have a look at this website:
http://www.bobatkins.com/photography...focus_EOS.html
Yes, many of those old lenses are quite good, I am using a lot of Canon FD lenses with excellent results.
I have one Sun, 200mm f2.8 prim elens, still lkeeping it for something, but it is not exceptional.. the antireflective coating is not very good. However, when I close it down to f4, it is acceptable even for AP.