Don't get me wrong, I like guitar pro... it's a nice program. However, I find it a lot easier to manipulate the information with powertabs. In Guitar pro right from the beginning you have End Bar... if you write your piece/song and then decide to add something... it's a pain in the neck... something that in powertab is quite easy to do. Another problem I have encounter with GP is that you can't use Musical Directions (DC or DS as coda, fine, etc) between repeat bars, because it'll triger the DC or DS at the place where you put it, cutting off whatever was after the MS. There is no way to tell the program do execute the DC or DS after the repetition. Also, it doesn't have ritardando/accelerando and no double dot (to add 3/4 of the note's value).
A cool thing about GP is that it allows you to print just the musical notation or just the tab or both. That would be cool on PT.
To print sheet music I use mainly Sibelius. Lilypond is nice, but after looking at how is the information entered, I didn't bother to read all that and opted for Sibelius. I must say that you can make some pretty spiffy scores with Lilypond tough.