I'm currently playing Flyff, which is ok. It has a lot downsides on it though, like Lag(especially on weekends), lot of grinding on later levels(i get 0,3% exp per monster while im lvl 50, and if i happen to die i lose 3%) and only skills are combat skills which makes it all revolve around Fighting. Guild wars is probably the only fun thing to do...which is the best Gpotato MMO, like the most pop.
i played space cowboy for a month or 2... and i loved it, untill i got to the zones where it forced you to PVP, cause my comp couldnt handle it, and even the grinding took twice as long on my stupid computer.