The plextor only writes DVD+R at 8x, but still only writes DVD-R at 4x. Now there's a lot of debate as to whether DVD-R or DVD+R is more compatible. Personally I've had greater luck with DVD-R, and from what i've seen so far, the companies that originally produce the media seem to be a bit more reputable among the -R suppliers than the +R suppliers.
Currently on
www.dvdrhelp.com they're saying -R is more compatible in their database of users reporting back wtih results of burn reliability and play back compatability.
Pioneer did recently announce a drive, the DVR-107/A07 that'st he model) that will do 8X dvd-r and 8x dvd+r. I think that comes out in January?
After that you'll start seeing dual layer burners and dual layer discs that can burn upwards of 9 gigs (roughly) per side.
Can't wait till blue-ray drives though, 27 gigs per side, mmm
-vasu