Let me answer largely from ignorance – in other words, see what others have to say also.
I don't think there
really is much difference any more to the world at large, but to people who already have DVD players there could be a lot of difference.
It seems some players like -R/-RW while others prefer +R/+RW.
I'd suggest checking our this page:
http://www.dvdrhelp.com/
And esp. this page:
http://www.dvdrhelp.com/dvdplayers
If you own some players that "like" -R, and others that "like" +R,
or you just don't know WHAT player you may want to buy NEXT year there seems to be a way our.
Buy a DUAL FORMAT DVD WRITER that will burn BOTH -R/-RW and +R/+RW!
Right now Sony's DRU500A and newer DRU500AX (about $350) are the only drives that can do it, but HP Lite-On and others have anounced.
These drives do about 2X in RW and 4X in R mode, faster than most single format drives.