Mine almost always goes 8x for burned DVDs, 8x for dual layer pressed DVDs, and 16x for single layer pressed DVDs. It's not a bad speed and it can read from horribly scratched, warped, rotted discs. Yeah, I just got a perfect rip from a "blotchy" dvd original.
Previously, I felt pampered by the 16x rip speed of my Sony drive, but it couldn't read every file from every disc. Now, I'm pampered by a BenQ that can read every disc.
I am planning to add a http://club.cdfreaks.com/showthread.php?t=107490 to my system at some point in the future because you can have a much more "automatic" experience by having two drives, and the addition is very inexpensive if your computer case has room for two drives. These will also work in a prolific-powered external enclosure if the computer is too small for two drives (like my tiny computer). So, now I have this tiny, modern-looking computer with a collection of wires and hang-ons that is larger than the computer. Oops! Anyway, when in doubt, use two drives.