The game itself is good enough for the $5 membership, but horrible loading issues and constant lock ups bring it down.
However, constant loading times and crippling lock ups can easily steer players away from the game. I don't believe it's computer performance issues, since I'm running on a computer that has more than enough power to run a game of its caliber, but throughout the game's world, you must load every time you enter a house, or leave/enter an island. The loading times can sometimes be quick and painless, but more often than not the loading times can take far longer than they actually need to. To add to the pain of constant waiting, the game continues to lock up while trying to move throughout the worlds of the game, which can usually keep you out of the actual game long enough for something to walk up to you and kill you.
There are some beneficial things to the game, if you're willing to put up with the lock-ups and loading times. Sailing can be fun, especially if done with friends. Although there isn't much variety to it, the interaction with your fellow pirate-friends can prove worthwhile. Also the quests aren't too burdening and easily draw you in. And the cut-scenes are well designed, and do a good job of capturing the characters and their voices.
I must admit I haven't delved into the game too deep, mostly because I just grew too frustrated with the lock ups. So there may be more to the game past the initial 10 levels, however, by the looks of it there isn't much to grow excited about.
If Disney can figure a way to fix all the loading and software issues, this game could prove to be a great, inexpensive way to spend time with friends online. But until then... it's not worth the time.
So to sum up:
PRO: Decent quests, sailing with friends, characters
CONS: You'll spend more time loading/locked up than actually playing