THe sony 810 is a benq 1640 rebadge! You get the sony 810 in 2 flavors, the OEM and the RETAIL...OEM for abt 2800 and retail for 3200 bucks. Only cosmetic differences, drive is the same ie. benq 1640! Recommended over the LiteOns.
The last OEM batch of Sony 810s have had some bugs with Moser Baer dvds, so be sure to check that up before you buy!
Happy burning!