1. DVD-R/RW format works fine. You can play DVD-R on almost all DVD players, XBOX and DVD ROMs. Yes, my friends bought dvd players 4 years ago, and they are very picky on media, however, they all read my DVD-Rs.
2. DVD-R media is cheaper, at least compare to DVD+R.
3. DVD+R format is stupid.
Yes, that format is stupid. SONY created CD format to collect royal fee and they succeeded. Then they created memory stick format and it is good. But no one will use it as there are many free formats. So SONY used to collect royal fees. They don't like to pay for it.
Now when DVD forum already create the DVD-R format like CD-R, SONY just don't like to pay DVD forum royal fee and created the stupid DVD+ format. Sorry SONY, I will avoid you as I can.