Mp4 all the way.
Any good contest coordinator knows that not only does the audience want videos that are awesome overall, they also want awesome visual quality. I mean, everything is 1080p this or ZOMGHD that, so it's the job of a coordinator to give the audience a sick contest that looks great. MPEG-2 looks like ass and the file sizes are huge. As for Mp4, it's smaller, better quality, and I've never had a playback issue that a simple re-converting didn't fix.
The best way that I've seen a contest run is with a computer as the main playback device and DVDs/Bluray as back up. Of course you can't just throw files on a disk, hell yes they can get messed up. But then again, any coordinator that just throws files onto a disk and says "cross yer fingers! I hope dis works!" shouldn't be coordinating in the first place. Lots of time + days of trial and error come with the territory.
I'll take a 70mb mp4 that makes my eyes melt with it's shinyness over a 200mb+ MPEG-2 that looks like it was beaten with an ugly stick any day.










