I've set out to plan a trip to WDW several times...each time, I just go back to DLR. The reasons are these:
1. Like everyone else has stated, the parks and resort overall are compact, and easy to navigate. We've got 4 kids and every time I read about taking a bus full of sweaty, smelly people just to get to another park, I think "No WAY am I doing that". LOL!
2. I've read a TON of negative info online from people complaining about the guests at WDW. Seems a great many people feel that certain ethnic groups visiting from other countries behave in ways that ruin their experience. We've had some issues here and there over the years at DLR, but NOTHING like what I've read other people have experienced at WDW. DLR is mellow, and I like mellow.
3. Last but definitely not least, I hate muggy weather. Orlando in August?!! No.Thank.You. We've only done DLR in August once, and it was for 5 days. And weather-wise, it was my favorite trip, ever. Super warm and sunny during the day (with no humidity to speak of), and beautiful, BEAUTIFUL evenings. Reading planning sites for WDW, a lot of people talk about heading back to their hotel midday just to change out of clothes soaked from perspiration, and daily thunderstorms. Um, yuck? With a family of 6, there's no WAY I'm going through the hassle of bringing 2 full outfits for each person for each day of the trip. I mean, it will just never happen, lol.
Those 3 reasons will likely always keep me from choosing WDW over DLR. When we are at DLR, we are totally comfortable...the experience is laid back. WDW seems, to me, to have a lot more potential for all the work and discomfort that goes along with it to make it impossible to get the experience we are looking for, and are able to get at DLR. I guess it all depends on what you're looking for.
Wherever you choose to go, have a great time!