I have the Roxio version that burns DVDs and the Nero cd-burner version.
I like the fact that Roxio adjusts the burn speed automatically. The DVD video maker software is kind of frustrating. Roxio has a good "burn selected files to multiple disks" feature. It's still kind of squirlley (sp?) though.
Personally, I prefer Nero. I'm not sure why. I like the interface more for one - I guess I'd compare the Roxio look to Windows XP and Nero to Windows 2000. It allows you to backup a disc to a Nero image, which is good because it lets you do it, but bad because it's proprietary Nero format, not the standard iso.
My $.02. Hope it's clear enough to help .