One of the many ways I use GPro is to get drum midi loops. Once you download the GP file I export to a midi file and open in my DAW and if you find a drum groove you like, split it into a 2,4 or 8 bar midi file and then save it. I have hundreds saved, even from songs I do not really like. This is great for drum fills too. Once you get it in your DAW you can manipulate it to your heart's content. I assume you can still do this in GP 8, I'm still on 6.
If I can find a good Guitar Pro file of a song I like I also create backing tracks to practice learning the guitar parts for. Ultimate Guitar.com has some good ones on the site along with some shitty ones also.