I am a reseller and have sold many dvd writers, LG, Pioneer, BenQ. I only had one BenQ returned and I believe it was an OS problem not the drive. I would recommend the BenQ 1620 over all others.
There are many reasons for so called defective units:
Shipping and Handling - If you could see how the units are handled by the delivery guys you would cringe.
OS - Lots of problems with OS's that are eliminated by a reformat.
Compatability - Some problems with certain motherboards.
Defective Computer Parts - IDE ribbon connectors are notoriously defective.
Careless Handling - Static charges when installing without grounding can kill a drive.
- Handling a drive roughly (more common than you would think)
- Even plugging IDE cable in backwards.
The above can happen with any drive, but seem to happen with BenQ a little more often, and I believe the reason is that more are sold.
So take all with a grain of salt. When you buy mailorder you can easily get someone else's RMA because they don't want to go to the trouble and expense of returning it to the manufacturer.
I deal direct with my customers and install most equipment myself. 50% of the time I have to reformat and setup their systems because they are totally corrupted. I have never had a DOA in over 15 years. My RMA's run at about 0.01%. I pick everything up myself from my suppliers, nothing by mail.
Hope this helps some of you new guy's who have questions.