I usually use -R but my laptop (which I'm using for typing this) supports only +R DVDs... so I have to have both anyways. My gut feeling is that -R is more compatible.
Few links:
http://www.webopedia.com/DidYouKnow/Hardware_Software/2003/DVDFormatsExplained.asp
http://www.proactionmedia.com/dvd_media_formats.htm
Few links:
http://www.webopedia.com/DidYouKnow/Hardware_Software/2003/DVDFormatsExplained.asp
http://www.proactionmedia.com/dvd_media_formats.htm