Have TrackIR Pro V4.00 Love it! I've been using it with IL-2 mainly and wouldn't go near a sim without it nowadays.
Yesterday I upgraded my system from Vista Ultimate 32 bit to Vista Ultimate 64 bit and have since had a small prob.
As you will be able to see from the image below, it looks like the top sensor on my Track Clip has stopped working. This causes all sorts of problems as you could well imagine. In addition, the image on the side is new too. I took the screenshot while sitting in a darkened room to minimize light getting in the way:

I have had my product about a month or so and given the price have looked after it very carefully indeed.