The original drive for scanning is Liteon. BenQ will also scan accurately but the scanning interval is more precise for Liteon and as some long time users have stated why would you use a drive for scanning that is less precise when you have a choice.
I would recommend the Liteon 1693. I have used one for three months now and not only does it scan well compared to other Liteon drives I have used, it also is one of the better burners I have tested. I have tested mine with TYG01, TYG02, TDK TTG02, Ridata R03, TY T02, and Verbatim MCC 003 at 6X and they all are rated AA+ or better by my standards. This means they deliver very low max error levels (PIE from 5-20) and total PIE under 75,000 with total PIF under 250.