This is the one I own, a
Gigabyte GTS 450, which surprisingly still costs the same price it was listed for when I got it (but I got mine with a $14 discount) last October/November.
It produces in general around 9100-9300 Points Per Day, depending on the WU and what I'm doing, and every once in a great while somewhere ~15000 PPD (the Project 10928 it folded yesterday, for example, took 87 minutes 25 seconds and netted 15237 PPD), but those are quite rare and take quite a bit of CPU time, such that the -bigadv SMP WU I'm crunching at the same time slows enough that I end up gaining only a few PPD overall. The GPU is fairly quiet, but then I'm probably a bad judge because I've got 3 systems chugging away in close proximity, 2 of which also have GPU's folding.
The card isn't a great overclocker, since the shader and core speeds are linked at 2:1. I haven't overvolted to see how much that would help, however.