I have a few options, the NEC 3520, NEC 3500a, and Sony DWD22A
From these 3 I would say NEC3520, but why are you limited to these options?
If possible the BenQ1620 and the LG GSA-4163B are also great drives, with the latest being my favorite because of the DVD-RAM support.
I also would choose the NEC from the list you have, but the chances of actually getting a 3500 anymore are close to zero. I agree with the LG quality and features, but the NEC will do bitsetting on both +R an +RW with hacked firmware, if you want this.
NEC is much better than a Sony which is a re-badged drive and overpriced. If you want to spend more than a NEC, get a Plextor. But the bargain priced NEC and Benq drives are high quality and a great bargain.
What about Pioneer VDR-109? I’m Installing one in my system. Haven’t burn anything with it yet.
Sorry, DVR-109, that is.
The Pioneer 109 is a very good drive as well. The next drive I get will be a Pioneer, not to replace anything but to add to what I have. It has the additional benefit of very fast ripping with a little hacking. I don’t see much modified firmware and I don’t believe it will do bitsetting though.