My business produces video documentaries on DVDs authored on Macs. We've found that some DVD players will play these "home-burned" DVDs and some will not. In order for our clients to use them, we've had to resort to buying DVD players we know will work and giving them to our clients.
It seems that there are two ways to burn DVDs, and I don't remember what they are called. The method used to make the commercial DVDs of Hollywood movies is very different than the method used by a burner in a home computer. There also seems to be a disparity in standards, or perhaps a looseness, in the burners for computers.
I thought of using DVDs as a promotional device, too, but dropped the idea after I saw how much trouble we had with playback.
juan