I seriously DO NOT see any difference between using DVD+R's and DVD-R's. I'm with the +R camp, since my DVD player read them better than the -R's.
If one doesn't work, the other will. I haven't seen any difference whatsoever. All that sh*t about "+R's will burn out your lens faster, use -R's" is a bunch of snake oil.
Bottom line: Use what works in your system. Both cost the same, and some stores have decent return policies. If the first type doesn't work, return it and go with another.