I was having problems with my 17" SLI enabled gaming laptop crashing and I was pretty sure it was due to heat. Both graphics card idled at around 65 - 70c and went up a few degrees more during playing until games were crashing (on a freshly installed xp installation with the graphics cards fans as dust free as possible).
Using the cooler has solved my problems. Before I could only play Civilisation 4 for about 15 minutes before it'd overheat and crash - now I can play for as long as I want. My laptop gpu's now idle at about 55c-57c when the cooling fan is on.
After stopping a 2 hour gaming session they were idling at about 64c - pretty much the same as with no fan installed, but by then I imagine a lot of internal heat had been generated and would take quite a while to dissipate.
Installing the card is really easy. All you have to do is set the base at the correct angle to support your laptop, then adjust as couple of clips at the front of the stand. Plug the fan (2300rpm and quite quiet) connector into the usb socket and it'll start to cool your laptop. How much of a cooling effect you'll get will also be determined by where the air outlets are on the underside of your laptop. Also, whether the cooling is more due to the fan or the effect of lifting up the laptop, or both, I'm not quite sure.
My laptop spilled over the base by a couple of centimetres on each side but was solidly enough supported, and it was easier to type due to the keyboard being angled by the stand. The stand can also rotate should you wish to do so. While you can put the base on your lap I wouldn't really recommend it if your laptop is heavy, as the plastic base will start to dig into your legs.
All in all I'm happy with this product and would recommend it as it does the job it says it does.