Hard for me to make a direct comparision between the Subaru OEM and XtraVision bulbs:
I have the Sylvania XtraVision's in my SE-R. They are brighter than the factory Nissan bulbs.
Also running Osram Silver Star's in my WRX (EDM projector low beams). Much improved lighting compared to the factory H1 bulbs.
I would highly recommend Osram Silver Star's and have also heard good things about the Philips Vision Plus bulbs. FWIW, both claim "50% more light". YMMV.