MAGFest is awesome because:
24 hour arcade that has most things you'd want. Multiples of pop'n, iidx, sound voltex, para para paradise (THERE WERE THREE THIS YEAR) and pretty much everything else. Everything is on free play and honestly I could spend the entire con in the arcade. Getting drunk and then going to play rhythm games at 3 AM is an awesome experience.
It's at the most ballin venue ever. It's a swanky hotel that is built just to have conventions... there is basically a little mini-village at the bottom of the hotel, and everything else you'd need (except cigarettes and hard liquor - buy those first if you want them and go to MAG) is available within a 5-minute walk of the hotel. There are many restaurants, a CVS, a little grocery store that has beer and wine and basic groceries, and some cute little tourist-y shops.
Super awesome musical guests. There is a designated chiptune space and they usually get really cool chip and non-chip guests. One of my best convention moments ever was seeing a composer for Katamari Damacy (Yuu Miyake) do a DJ set, with a friend of mine whose favourite game is also Katamari! We had a blast dancing and freaking out... it was just an awesome moment. Another awesome moment was seeing Chipzel at MAG, as she is a chiptune idol of mine
anyway....... Anime North will be fun too ^^ it's the people who make the biggest difference honestly. BUT Mag is fucking amazing, honestly I will never miss it again if I can avoid it