ATP's Tough Drive Mini is a great USB stick that is designed to last. When we tried to break it, it didn't take a sweat and held our data safely. Not only is the stick rugged it also offers excellent performance in both bandwidth and access time making this a great choice for Windows Vista ReadyBoost.
The price of $50 seems to be justified but it is high if you compare it to a noname product. Even when you assume that you will break a cheap stick some time, it should be cheap enough so that you can get a new one and still stay within the price range of the ToughDrive. However, if your data is important and you can't afford to lose it the Tough Drive Mini from ATP is certainly the better choice.