Go with Goofy's kitchen if your trying to decide. You won't be disappointed. Areils Grotto is great character interaction but the food is terrible. Yes these are the only two character dinners available.
Another vote for Goofy's Kitchen. Ariel's was OK, but less character interaction. Plus you have to get a ticket to get into DCA. On the other hand, the cost to eat at Ariel's is cheaper and you don't have to leave the park to eat.