The 1620's are good drives all round. Very good readers and excellent results in burns for me so far. You can use Nero CDSpeed (a free program to download if you don't have the Nero Burning Suite) to check for errors in your burn. You can download it here:
The disk quality check is under Extras.
If you get the retail version check the firmware that comes with it. You'll want to use the B7P9 or B7T9. Both are official firmwares available from BenQ