Interesting DVD-R vs DVD+R Compatibility Test
 

CDRInfo.com chose an equal number of dash (-) and plus (+)format recorders with an equal number of respective media and tested one-by-one the readability of the burned discs on about 5 dozen players.


http://www.cdrinfo.com/Sections/DVDMediaFormats/

Our own little study has given the same results. We've tested both + and - and found that the majority of players like the -R. One player model not listed on that table happens to be in my house: JVC RX-DV3. It definitely prefers -R. It's frustrating, because the multi-format burner I purchased for video only likes +R disks. :(