I read an article on this subject some time ago and really don't remember much of it. DVD+r has more options or features than DVD-r. It allows you to do more things or include more info on your burn. Do a search, I'm sure it is very easy to find the differences. I have used only DVD+r for a couple years with no apparent problems. I have 9 Linux distros on DVD+r . They all work.
i5 3570k, ASRock z77 Extreme 4, 8 Gb Ripjaws 1600, Antec 430w psu, HVR 1600 tv tuner, custom case- marble top, oak face. Carver & DCM Time Window sound system. Mint 14 KDE.