. Pioneer and NEC are based on the same chips, but there are differences in firmware. Not sure if there are any differences in the optics. But those are probably the two best cheap drives (and their derivatives - e.g. the Asus is Pioneer, etc. - though the Philips-based Benq has quite a few adherents. DL is overrated at this time - most that have DL drives don't do much if any DL burning because decent media is so danged expensive...
IMO, the Plextor PX-716A is excellent, but it only comes in a full retail kit. If you can find the Pioneer in an equivalent retail kit, the prices will be nearly the same.
. The Plextor PX-712SA is a good buy right now because of a $20. rebate program. The PX-712A is one of the best optical drives ever made (one of the few to get 10s in reviews on respected sites) but it is single layer. And the SATA version, which this is (the PATA version being very hard to find now), has limited compatibility with integrated SATA controllers (mostly compatible with Intel or SiliconImage based controllers). Luckily SiliconImage add-on SATA controllers are cheap and readily available.
.bh.