Thanks all for your replies, I've got a lot to think about. The thing that confuses me is that there are often many versions of a lens, with different specs, markings, etc. I read one thing and think, "Awesome, I'll look into that lens," then discover some small difference between models mentioned somewhere that makes me wonder what the hell I'm looking at...

So, do I take it from this thread that there's no love for the APO-Symmar or APO-Sironar N 72º?