It depends on what you like:
Majestic Prince looks to be the best one for comedy and CG action.
Gargantia has Urobuchi Gen and it seems to be lively with neato background art.
Valvrave is Gundam that is not Gundam, with lots of drama and school-based characters.
So far, the order I listed looks to be the order of descending quality, but nobody knows right now! Any show has a 33% chance of being the best one of the set.