i have the seagate 7200.4 500gb (without g sensor) and it works perfectly. i still get 6-7 hours battery life on 40% brightness, browsing, itunes. it runs just as cool as my old 5400 (a few degrees hotter, when im working it), and i dont notice any considerable vibration or noise. the speed is great and really lit up my macbook especially with 4gb of ram.
the older versions of this drive were the ones giving the problems, but now they're good. a customer service rep at owc told me this and he uses one himself.
also the seagate 7200.4 beats the hitachi 7200 in almost every single aspect when tested.