I've seen Hunter x Hunter, Phi Brain, and Fate/Zero so far.
Based solely on the first episode, Fate/Zero has been the best so far. If you liked Fate/Stay, then you're in for more of the same with some delicious backstory revelations. Type Moon may deal in cliches, but they do an outstanding job of making me not care. For shounen fare this season, Fate/Zero is probably your fix.
Hunter x Hunter didn't wow me with its first episode, though having read the manga I do know that the beginning is the weakest point in the entire series. Having had a previous anime adaption, it seems to be going the same route as Fullmetal Alchemist: Brotherhood in rushing through the materiel that's been already covered. Hopefully this will not be the case. The most recent arc may have been the greatest, but there's no reason not to take your time laying a solid foundation.
Phi Brain is sending out Yugioh vibes.Forget children's card games; children's puzzle games are the real srs bizness. It may not be good, but it looks to be entertaining.