Based on my experience thus far i'd go w/Sony...
I bought a cheap BackPack DVD+R drive first... brought it home... installed on my laptop w/USB 2.0 PCMCIA card... wouldn't work... ok no biggee prolly an issue w/the card...
SO I install on my 500Mhz Celeron W2K Server box... it has a PCI USB 2.0 card in it and had another USB 2.0 CD Burner attached already working great... still couldn't get the damn thing working... after 2 days of messing w/it and ruining several DVDs due to partial burns or failures I brought it back and got the external Sony USB 2.0 DVD+/- R/RW drive... thing is awesome... burns both + and - R media, rewritable and write once media...
I've heard alot of good things about the Sony Internal one too... so I say stick w/what works and go sony