I had the Aopen 1648. I had the liteon 163D. I have had Sony 720 RW's and NEC's, and Phillips 16ls that i converted to a Benq 1625.
I recently replaced the Aopen and Liteon with an Asus 616A DVD-Rom. And i have to in all honesty say it is the best DVD-rom reader i have ever saw. I had some disks that i thought were coasters as CRC's in abundance on them. No drive could read through them to make me back them up. The Asus glided through them without even a slowdown.
Amazing drive. Plus why on earth are you doing quality scans with your rom? Do them with your NEC, plus especially as i assume you burned the disks your wanting scanning with that?. Plus doesnt the Aopen drives do the scans at 16 ECC and the NEC at the standard 8 ECC for interpreting results. If so why on earth are you electing to do the scans with your Aopen.
(someone will need to please correct me if i am wrong on this)