What I like about easywdw are the descriptions - why the crowd calendar is what it is. Then I can easily adapt it to the way we tour. This means that going to a not recommended park has actually worked out great for us at times - but we knew why it wasn't recommended and worked around that. (For example, Epcot on a Sat of Food and Wine with evening EMH - so obviously a very crowded park. Our plan was just future world. I have never seen Epcot as quiet as it was that morning - as the F&W people were not there anywhere near rope drop. I have found easywdw accurate - but more importantly, the descriptions help tailor it to MY family, not just using a number.
*I've heard that touring plans changes their numbers closer to the time too - I'm not sure how accurate that is, just what I've heard recently. Easywdw only seems to change if something significant changes to the schedule/events.