I bought the Zalman VF-900 from Amazon.com last week. My video card, 6800GT was reaching temps of around 70C just by idling. There was a few dust bunnies but for the most part, it just seemed like the cooling system on the card was in adequate. I opted for the Zalman VF-900 because I’ve used its smaller brother, the VF-700 on clients’ cards before with great success.
For the most part, it was just a matter of following the directions that came with the heatsink. My only two areas where I ran into problems were: 1) forgetting to clean off the thermal compound/residue off of the memory modules and also tightening the mounts into the actual heatsink. If you follow the directions, and keep in mind what I just said, you should have no problems.
So far the cooler has been great. I don’t overclock but it’s dropped my temps by 20 or so degrees and has kept it there for the most part steady.
Overall, I would not hesitate to recommend this product. Great cooler and easy to install.