The real difference between +R and -R is that DVD+R has better defect management than -R (see the Wiki entry for DVD+R), though this is a benefit generally only seen by computers writing data. The real benefit that DVD+R has is that its rewritable version, DVD+RW, does not need to be finalized before being read by another player. For example, if I record a TV show on my DVD recorder and then put the disc into my computer, the computer will be able to play the video, even if I don't finalize it on the DVD recorder; I just won't have a fancy-schmancy menu to select from. There are other small differences, like drag and drop writing, but these probably don't apply to movie making. And DVD+Rs/+RWs can have their book type changed so that they "trick" players into thinking that its a DVD-ROM disc, a.k.a. a commercial-type DVD. Check your PC burning software for this; my guess is that most stand-alone DVD recorders would do this by default
Now, I've used DVD+R since we got a DVD Recorder in 2006. I have no idea what made me buy a pack of DVD+RWs over anything else, but I've used those and DVD+Rs since then, and have never had any compatibility issues. I even have an old Panasonic DVD player from 2001 that can read DVD+Rs from the computer and recorder just fine. And most of these early machines have either died by now or have been replaced by Blu-Ray machines with Internet connectivity, so I don't think the compatibility issue is that important anymore. I say go online to Amazon, pick a good brand like Verbatim AZO or Taiyo Yuden, and do the eenie-meenie-minie-moh. A lot more info about DVD burning and quality can be found at this website:
www.digitalfaq.org
Like old_tv_nut said, a stand-alone DVD Recorder like the Panasonic models will generally give you better results than video cards, except for professional (read: expensive) capture cards. A method I found that works great is use a stand-alone recorder to copy the VHS onto a DVD+RW (no finalizing needed!), rip it onto your computer, edit the video and make a menu for it, and then burn as many copies as you need onto a +R or -R disc. You get the great quality of the DVD recorder, and the editing ease of your PC.