I grew up near DL and have visited many times. We spent five days there over two trips in 2005. I am planning my first trip to WDW for early May, and will know more about how they compare after the trip.
One thing to point out is the difference in hotel situations and the proximity of DL and DCA (which I would recommend visiting - parkhopping is free for multi-day tickets at DLR). The walk from the DL gate to the DCA gate is about one minute. There are three resort hotels, and a whole slew of "good neighbor" hotels. Some of these are very close to the DLR gate - an easy 5-7 minute walk.
If you get a close by hotel, you can walk everywhere. We never drove our car or boarded a tram or bus for four straight days last summer. That is very convenient. And afternoon breaks are easy to do and recommended.
As for rides, the strong rumor is that Test Track is coming to DCA (in response to an earlier post) morphed into a theme based on the upcoming Pixar movie "Cars". I originally did not like Indiana Jones very much, but after about three or four rides it became one of my top three favorites at DLR. I will miss that at WDW, but am looking forward to some of the other originals there.
The new "Remember Dreams Come True" fireworks and laser show for the 50th anniversary celebration is jaw-droppingly fabulous, but only if you squeeze into the hub with a gazillion other people (we did it and it was worth it). You cannot see many of the effects from outside the hub.
And in California, we called the soft drinks "pop" or sometimes "soda pop".
