What ones have you played? I've played quite a few, and forgetten a number of them.
Also, I have left SMT:I behind until OB begins. My latest game (after several flops, of which Zero Online was one) is AirRivals, an arcade-flyer (a la simplified-Ace-Combat) with RPG elements. Definitely more of an Action-MMO than most, it kills the concept of botting. After the tutorial, you choose your faction (either stick with tutorial faction, or betray them and join the rebellion which is starting to overpower them, though only in the story). Most stick with the first faction, so if you join the rebels and fly PvP, you'll be outnumbered 8-to-1 on a good day. I joined the rebellion because my XO in the tutorials pissed me off, and the rebel XO had an awsome eyepatch. I've been enjoying my choice so far, mostly due to a lack of death penalty.
...that post just doesn't flow. Ah well, I'm too tired to rewrite it.