I've grown up with Walt Disney World, so by default it wins. Further thinking about this, the idea that "it's bigger" isn't the best stance because it really doesn't do what does have to offer with its space justice. Yes it's bigger, and therefore makes room for much more activity, but WDW was really the first park Walt contributed to in detail.
DLR was the first park, but Walt always said it wasn't what he intended. WDW - Magic Kingdom and Epcot - that's what he wanted. Not Disneyland. Given this, so much more detail and effort went into the plans for Magic Kingdom and Epcot and so much more came out of it. Across the resort, there are tons of things that honor Walt's desires for it, so much attention to detail and so many options that you just have to plan to stay at least a weekend, or a week, to do.
Disneyland is cute, it's fun, but it's not really a stay overnight resort. That's never what I got from it when I went. But with WDW, I really feel like I could stay one night and have a completely different experience the next day. They pay really close attention to the themes all across the resort. Disneyland doesn't really try to emphasize themes, you're just there to have fun for the day.[DOUBLEPOST=1416601415][/DOUBLEPOST]also, I did this cool backstage tour of Magic Kingdom and the tour guide emphasized that the name of the resort is Walt Disney World, not "Disney World". Walt's brother Roy made sure to put Walt's name on it to emphasize that it was his brother's park, not the company's. Walt died a little ways into the construction for Magic Kingdom and it just felt really special to Roy for it to have his name. so like, please don't call it "Disney World", it kind of disrespects what it's supposed to symbolize.