I'd have to disagree with some of that...and please keep in mind that not everyone can burn to the same formats (to find out which ones you can, go to the "About your Mac" option in the apple menu, select it, then select "More info" and click on "Disc burning"

...I've found that most of the issues relate to the age of DVD players. I have a friend with a very expensive Denon DVD player that costs thousands years ago...it can't play many DVDs he created, yet a newly purchased $60 player from the supermarket copes fine.
The first thing I tend to ask if someone has issues with a DVD I make (and I tend to burn in DVD-R mostly) is "How old is your DVD player>" and then "Have you tried it on another machine?". In one batch (going out to about 100 people) this was always the issue
Also...my golden rule when buying blank DVDs is "buy to the speed"...so if your DVD player says it can burn at 4x speed, then buy SPECIFICALLY that speed...not ones that bill themselves as 1-8x speed or anything like that. It gets increasingly harder to find discs with a specific speed at times, but when I do, I have few issues with burning and viewing.....or that's just what I've experienced.
Phil