I use my DVDRW with the newest Nero and I have no problems. I don't drag and drop, but Nero is so damn easy and fast, I never have a problem.
I also use 321Studios DVD Copy and backup all my DVD movies. Then play them in a regular standalone DVD player. Can't do that with DVD-Ram.
You can get 4.7G on one side of a DVD. For me, that's plenty of room for anything. The DVDR discs are $69 for 100 at hypermicro.
I would stay away from DVD-Ram and get a DVDRW. Some new 4X DVDRW units have come out.