I've driven the GTI, but not the Volvo. I did read what Car & Driver said about it, and they said they'd actually prefer the GTI. Also note what they said about the transmission choice.
http://www.caranddriver.com/reviews/...ign-quick_spin
BTW, you know it's easy to add more power to the GTI, right? There's tons of mods, some as easy as a chip.