Not a great fan of Tiptronic, although my wife has had it on a 964 Cab, 993 Cab and 996 Coupe. However, even she has now reverted to 6-spd manual (987S). IMO the Tip compromises control and throttle response, and yet the manual transmissions are so good, particularly on the later cars.
But, being torque convertor technology, the Tip system should be very reliable (although 964s were first generation) and I'm not aware of any problems other than the occasional electronic gremlins. We once had a juddering upchange, and this was rectified by Porsche by using a higher quality synthetic auto-gearbox oil. Mind you it was expensive - £100!!! (under warranty).
One advantage of a Tip, being an auto, it is less likely to have been thrashed. The gearbox will have controlled the engine speed. So no over-revving through missed gear selections.
