I think you should never rely on tabs. If they are made by fans, they usually go wrong in the difficult parts. (and sometimes in the easy parts too) You should always try to listen to the song yourself from the CD of mp3. (mp3s can be listened to at a lower speed, which helps a lot) You can use tabs too, but you should at least try to check if they are correct.
And what comes to Guitar Pro, I think it sucks. The mid makers are not that better at hearing melodies correctly than the tab makers.
One good example is the intro riff for Downfall. I´ve never ever seen a correct version of it, though it is possible to be heard from the CD (which I have succesfully done). Another good example is the chorus part melody. Everyone seems to play it wrong.
The guitarist of Sonata Arctica, for example, said that he´s really unsatisfied with the fans´ tabs.
