I have priced out both before and the answer is, it depends.
For us, flying to FL is much less money. Shuttles to and from WDW area are cheaper. (For that matter, rental cars have looked cheaper, too.) Most hotels that have shuttle service from the hotel to the parks are complimentary, instead of having to pay for it. When you stay onsite, it's cheaper. I've seen onsite value hotels at WDW cheaper than offsite at WDW and offsite at DLR, especially if you add in the savings of not having to pay for shuttles to and from the airport (WDW's shuttles "Magic Express" is free to WDW resort guests). The cost of food IN the WDW park is much less expensive for kids than DLR. Just an example, most children's meals in DLR are right around $6, while many of them all over WDW are closer to $3 or $4. Adult food is about the same for CS. I think overall, table services options are more varried and you can get meals for less than at DLR, but that's making particular choices. I think the Dining Plan at WDW is pheonemenal, at $39 a day for adults (that includes a TS, CS and snack each day) and $11 for kids.
The tickets are generally more expensive at WDW, but end up averaging about the same when you start to add days. At DLR, the most you can get is a 5 day pass. Going rate for that is 189 online, if not during the special right now (that's still discounted rate, though). If you want to do 7 days at DLR, you'd have to add passes. The cheapest way I found was to add a 5 day and a 2 day for a total of $311 for adults and 261 for child. At Undercover tourist a 7 day hopper is 259/226. Even adding the water park and more option to the 7 day hopper takes you to less than what the DLR 7 days cost for an adult at DLR, $304 for the park hopper w/waterparks.
In my "playing" I think WDW can be the better deal for longer stays, but shorter trips DLR ends up being a better deal most of the time. Once again, depends upon a number of factors.