"+" Advantages: Speed & Reliability
The "+" camp has a number of advantages:
* As someone else mentioned, Mt. Ranier support
* Erasing speed: Erasing a DVD-RW takes minutes while a DVD+RW takes seconds
* Writing Speed: The + camp has always been ahead of the - camp. When DVD+RW came out in Oct 2001, it was writing at 2.4x while DVD-RW was writing at 1x. DVD-RW only recently got boosted to 2x. DVD+R started at 2.4x, and both -R and +R are now at 4x. Oh, and + drives write CD-R and CD-RW faster than - drives.
* Reliability: Even though you can write to DVD-R at speeds greater than 1x, for *serious* applications it is recommended that you only write at 1x because of all the write errors/corrections at 2x and higher. Check out the DVD Studio Pro forum on Apple's Discussions page for evidence of this. There is *no problem* writing to 2.4x or 4x on DVD+R or DVD+RW.
* Compatibility: One area that didn't quite live up to the + hype was compatibility. The + group promised much higher compatibility with DVD players before their products shipped. After they shipped and comparisons were done, +R was shown to be about as compatible as -R, and +RW was shown to be about as compatible as -RW, so no biggie here. However, Trai Forrester (a somewhat eccentric but very smart DVD expert) has recently stated that at "reasonable" data rates (6 Mbps or less), + is much more compatible than - ; it's only when you get to marginal data rates (near the max of 9.8 Mbps) that the compatibility of + goes down to near that of - .
But overall I was much happier with my PC's + writer than I am with my Mac's - writer. If Apple supported both + and - I would be much happier. And that way, you wouldn't have to worry who won the wars because your Mac could do both.