I like the +R discs better, because they can be booktyped to DVD Rom, which makes them more compatible with standalone players. Not all burners can booktype though. Here is a little info on booktyping: http://www.k-probe.com/bitsetting-booktype-faq.php
and here is another good read on both -/+ formats: http://www.cdfreaks.com/reviews/Why-DVDRW-is-superior-to-DVD-RW/