There is a technical difference between DVD-R and DVD+R but for the end user, such as yourself, there is no real difference. Nowadays almost all DVD recorders support both formats and most DVD players can read/play both formats. The most important thing you should check is if your players support DVD-R or DVD+R or both. You can do this by visiting www.videohelp.com (go to List > DVD Players and search for your player).
Personally I prefer to use DVD+R discs mostly because they can be turned into DVD-ROM discs via BitSetting for increased compatibility (your DVD recorder has to support this though). DVD+R media also used to support higher recording speeds but this is not true anymore (except for Double Layer media, DVD+R DL has an advantage here). Last but not least, quality DVD+R media is easier to find where I live than quality DVD-R media.