i must disagree i too have verbatims but i have used memorex dual layers from walmart and i have not had a problem and i have been using them for a year now but by all means verbatim is the best but memorex works just as good.
I always used to use the Verbatims (the cheapest place I found to buy them was Sam's club - you can typically get a 50 spindle for about $60USD). Anyway, for kicks, I decided to order a 50 spindle of the Amazon.com for $33 and so far they haven't been too bad. I've had two bad burns out of about 15 discs, but since they're half the price, I'm fine with that. I haven't had any problems with the discs that completed burns, either.