Adapting FD to EOS seems like a hassle, i know mike blatt did it and sounds like the adapters double the focal length, they probably drop the IQ a little, there are a lot better 50mm 1.4 vintages lenses out there.
The biggest disadvantage I am seeing is the crop factor mainly. But cheap cheap cheap is awesome. And i found a dope 50mm f/1.4 and 70-200mm for plus a canon ae-1 and flash for under 100 bucks.... sooo
I have a couple of older ones... 135 2.5, 50 1.4, 24 1.4 and 28 2.0 I got at a thrift store.
I have done some tests but never used them for production. I'm not the biggest fan of the colors they produce, but they still have a unique look. At the same time the adapter I've used doesn't cause any problems, it doesn't crop the lens any further, the adapter I use allows the lens to still be the same and the only crop is based on the sensor being used. Although they do adapt better to PL mount.
Regarding sharpness there are no issues. They've actually been sharper than many of the newer Canon lenses. I do however really like the 400mm 4.5 FD lens.
I'd recommend either Contax Zeiss or Leica R's for manual focus lenses based on performance. I personally decided to go with Leica's for the looks they use. Watch Keh.com and you can sometimes snag the BGN lenses for around 3-500. The 50 2.0 is my favorite and is optically sharper than the 50 1.4 at higher stops.
have you had many good experiences buying bin lenses? personally I don't really care what a lens looks like on the outside as long as the glass is clean, but it seems like a big gamble sometimes. With that said, I have heard that the ratings on keh are very critical, in that even their lowest can be a 9 out of 10 by other stores
treadmills are the trick to everything. fat chicks, skiing on grassy flat back yards, OK GO videos.. - jibnut
Sounds like everyone said what I wanted to say.... STAY AWAY FROM FD LENSES
Get a pentax 50mm f/1.4. They cost ~$100-120 on ebay and are sharp as a tack. Just as sharp if not sharper than my canon 85mm or tokina 11-16. The adapters are also much cheaper than FD adapters b/c they dont require the extra lens element.