Disneyland PARK is much better than the Magic Kingdom. It has much more to do, better theming, and is just more fun. It is not better than the Disneyworld complex as a whole, but the park itself is far more entertaining than the single magic kingdom park in florida.
Space Mountain is just so much better in CA, Matterhorn is great fun(ride both sides, they are different) and Splash mountain is better. Thunder Mountain is different, but about the same in thrill factor. Indiana Jones is just plain amazing IMO. Even the fantasyland and toontown rides here are more plentiful and higher in quality.
I would say it is definitely worth the price of admission, even though it will be crowded. (Always is) Disneyland is a very different experience than the Magic Kingdom, and everyone should take a trip to both if possible. As for DCA, I can't say, I have yet to go there. Have fun!
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Saviour machine aka Squeemu!