After much research I came across the tablet Aiptek Slim 600U that really meets all of these requirements easily. Despite its compact dimensions, it has a relatively large working surface, is light weight and with 1024 pressure levels and the great resolution in the price range is simply unbeatable. The processing of the tablet is surprisingly good.
Connecting the tablet to a Mac Book with the supplied driver CD easy. Working with Adobe Photoshop and Illustrator is going very well.
Since it was satisfied all requirements and discovered no real weakness and an exceptionally good price / performance ratio offers, it gets to me like the full star number.