I have to tell you, if you sit down and figure out how much you will spend on the cost of the dining plan (you don't say how many kids you have) and what you will save on your room rate, you just may make out pretty good with the AAA discount on the rooms.
Last year we stayed at the Beach Club in September with a AAA discount. When
free dining came out, I changed and went with it, but it wasn't THAT much of a savings altogether over the AAA rate. A LOT depends on what resort you are staying at and how many people you are going with. Best deal with free dining is definitely at the value, but the mods and deluxes have great AAA discoutns, too. Where are you staying?
You can go to
www.aaa.com, click on Travel, then Hotels, punch in Orlando, your dates, then down the bottom click on "Disneyworld Hotels", and it will give you all the AAA rates for the hotels that are available. (You can browse and get rates, but must be a member to book) You can then add the cost of your tickets (from disneyworld.com), the dining plan, and there you go. If you figure the cost of a regular package out on disneyworld.com, the difference is your savings. And if you are going for two weeks, that will be pretty significant. Or, just call a AAA
travel agent and she can quote it for you.
Remember, you get so many other discounts/advantages for your $50 membership, not just room rates. Check it out!!!
To answer your question, it is DEFINITELY worth it to join, if that is the only discount you are able to find.
Good luck!