I prefer to take my children, ages 2 and 3, to Disneyland over Disneyworld because it is closer to where I live in Arizona. Both are very expensive and any help in the wallet to help lower the cost is nice. Also, I find that Disneyland is better for children under 5.
Disneyworld is closer to most of the US population, including the Southeast, Northeast and Midwest, and Disneyworld is considerably larger than Disneyland. By all measures, Disneyworld is better than Disneyland, and it was also the first of the two theme parks. Disneyworld has more attractions and hotels than Disneyland, as well as nearby theme parks.
I feel Disney world has more creative rides than Disneyland. They have more hotels and parks. Plus new technology. I live close so it is easy to get to. All the rides, even the not Disney made like rock and roller coaster, have there own Disney flare. That is just my opinion.