Compatibility - I am not sure how well the Sony is supported, but I know that the NEC will work IF you download the Mac drivers from LaCie. See, LaCie sells NEC drives, and so they wrote drivers to make them compatible with Macs running Panther.
Reliability - Sorry, not sure about those. I'd trust NEC a little more than Sony, but I have no data on the reliability of their drives. What I do know is that they can only burn dual layer DVD+R format, not DVD-R, and only at 2.4x. It's quite a limitation, but then again you can always use single-layer discs to burn at 8x in either format.
Vendors - I buy everything from NewEgg. Go there, you'll get a good deal, and it'll be shipped for cheap or free. I usually get stuff two days after placing my order, just when using the standard shipping method.