I have one of the cheap countertop models from Sony and tried to copy a recorded (and finalized) disc in Sonic Record Now. It froze my computer that I use for video editing, which has plenty of CPU and memory.
http://www.sonystyle.com/webapp/wcs/stores/servlet/ProductDisplay?catalogId=10551&storeId=10151&productId=11039219&langId=-1

Just a day before, I was able to copy a computer burned - dvd and burn it to another + disc. I really want a better dvd recorder so I can record all my video camera tapes to dvd in high quality. The sony device records a fairly fuzzy picture compared to the original tape. Not only would it be a good backup to tape but I want to make direct disc copies. I hate having to play a tape through 10 times to make 10 copies. I know recorders with a built in hard drive could copy direct like I want but would I need one? Shouldn't my computer also work?