I havent seen compelling evidence showing any brand being far and away the best. But I have seen some impressive overclocks with Leadtek,Visiontek and Gainwards. I've heard of some serious PNY O'C's as well.
As for personal experience. I have a leadtek ti-200. I cant "confirm" wether or not it has the exact same image quality as the leadtek ti-500 it does seem VERY good to me. On the OC front this card is Absolutely Phenominal. with STOCK cooling (not even a case fan blowing on it at all!) I can run it all the way up to 245/550 without any artifacts in 3dmark 2001!!! I'm willing to bet I can get even more out of it if I mounted and 80mm on it blowing on the ram and put a better gpu cooler on it. My personal goal is 275/600 I'll get there some time.
I score 7200 3d marks. in 2001 at 1024x768x32bp. My system is a ECS K7S5A with 512Mb Crucial cas 2.5 DDR and an XP1600+ running at 1.45Ghz. I think this is a pretty good score for a ti-200 with only an xp1600+.
Thats 28.6% OC on the Core and 27.3% OC on the memory.
This is from my personal experience. Also check out the ard forums. there is always alot of talk about ti-200's there.
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