The FAQ at the top of this forum is a good place to start:
http://www.disboards.com/showthread.php?t=1023429
It contains links to the description of the plan, and lots of information about the details.
Character meals, especially Cinderella's Royal Table, hold the distinction of having among the lowest "credit-to-dollar ratio" -- If you use your credtis for breakfast with Cinderella, for example, each credit is covering about $16 + tax + tip as compared to paying cash. Contrast that with Le Cellier, where each credit could be covering perhaps up to $46.97 + tax + tip (and that's without even ordering the most expensive items on the menu). Even if you ignore appetizers and desserts, you're still getting a cash value for each credit at Le Cellier of about $29 + tax + tip. So as you can see, just looking at the money side of things, Cinderella's doesn't work out well. However, Cinderella's is the most extreme example. Most of the other character
dinners work out better, financially, some coming in close to how much a restaurant like Le Cellier comes in if you ignore appetizers and desserts.
If you post where you might plan on eating, for each of your nights, someone might be able to give you a quick financial analysis to help you understand whether it would be "worth" it, how much it would cost, etc.