I have the OEM (NU DW163) 1620, and it's working like a dream here.
The problems you described are, without doubt in my mind (which comes from 20+ years experience), machine/os oriented. It might be as simple as cables, as convoluted as IDE-drivers, or something with the application used for burning.
Maybe, just maybe the drive is a problem, but all too often one tends to blame the newest addition to a system. While there may be some logic to this, it is no more than about 35% the case - instead, the addition of a new device may cause an existing problem to emerge, where once it lay dormant.
Tell us your machine configuration (CPU/RAM/OS), all of the software you have for burning (and any related things like DirectCD/InCD), and especially list any VSO software you may have.
Make sure you don't have IE running while burning. IE is among the worst offenders for locking up the machine.