As the saying goes, you should never purchase the first version of Apple products since they have been known to ship with a few kinks that must later be worked out. As it has turned out, the MacBook Pro, for all its praises, is no exception to this old wives' tale. Users have reported issues of irregular Airport connections, screen flicker when the brightness is set to the lowest setting, and uncomfortably warm running temperature, especially over the F key. As a result, Apple, which has admitted that these issues do exist on more than an anecdotal level, has started to replace the motherboard inside the computers. Starting with revision D (serial number W8611), Apple has fixed many of the reported problems and will be replacing affected MacBooks with this newer version at customers' requests.
Apple Addresses MacBook Pro Issues [DailyTech]