I almost always prefer my romance series to have at least somewhat happy end
(think Hantsuki). One could say i prefer a dramatic (perhaps even tragic at times) story, but with an ending on a positive note.
Not saying than not having one takes away anything or makes me enjoy it any less (i love Air ^___^), but it is still my personal preference. Though a happy end for the sake of having one is something i hate very much >.> (think Mai HiME).
My prediction for this one - bittersweet anding at best
