I'm glad those without MCE finally have an option that works. I tried it and it worked just fine although for now I"m sticking with MCE for a couple of reasons.
gbpvr - the good - works fine. low cpu usage during recording (medium setting) 2% on my box , ability to set bitrates, epg setup is painless if you live in a zap2it area, less bloated than MCE. It's free, you can't beat that!
-the not so good for me - memory intensive, far more than MCE, I'd have to figure out girder to set up my sapphire remote.
That said, I think Sub has done a fabulous job and if I didnt already have MCE I'd happily be using GB-PVR.