I have the NEC3500A and I like it, althought quality testing would be nice. It rips slower than some of the other drives, and if you don't flash the firmware, it rips twice as slow as some drives.
The Plextor is one of the best drives, although what you pay for is what you get. They rarely release firmwares for future upgrades. Also, the Plextors are a bit picky when it comes to the media they burn. I know some brands do not burn well on Plextors.
I really wish I had bought a BenQ drive right now, the firmwares are pouring in, and they do support media testing. They burn well, rip well, and read well.
I would not suggest the LiteOn just because some people have had issues with it. I'm not saying it's a bad drive by any means, it's a damn good reader, I'd just recommend other drives in this order.
1) Plextor (Although I cannot justify it's price, even though they are great)
2) BenQ
3) Pioneer / NEC.
Edit: I loved my Lite-On CDRW, but DVDRW is a different ball game... as I am learning!