Let me start off by saying this: I haven't played muchof the single player that Phantasy Star Universe has to offer, I stopped after a few hours when i realized that it sucked. But although I wouldn't recommend the single player to anyone, the online multiplayer is where it's at.
I can understand that the onlne isn't perfect, especially right after the game's launch, but the new expansion pack that was released adds quite a bit to it, and also fixes some of the original problems. Weapon upgrading has been fixed as well as more missions, items and classes added.
As far as Console MMO's go, PSU takes the cake. Unfortunatly, that isn't saying much. There are many people who just can't seem to get into this game, but there are also people who absolutly love it, some don't even know why. This game is really a hit or miss.
I personally love the online MMO, and would say that it is worth the 10 bucks a month. I think that Sonic Team has the potential to make a great console MMO with the next Phantasy Star game if they fix the problems with this one.