in terms of dvd-r quality
Probably the Pioneer DVR-108.
I would vote for the NEC 3500. It is possible that the Pioneer 108 could have better burns than I have, but any improvement would be theoretical.
Both my 3500’s burn best to -R media - EXCEPT the Taiyo Yuden 8x +R’s
Read some stuff about the 108’s over on the Pioneer forum and the 716’s over on the Plextor forum and you will see that there are hella more satisified 3500 users IMO-