I purchased the 3 month version to plan our trip in February. I was miffed at the fact that they don't have data for Sundays. When I wrote to him (the creator) and asked for a refund due to this fact, he pointed out that he does mention this on the website somewhere, and to just try it out on Saturday's schedule instead. Well, since we ended up going on a rainy Sunday in February, we found we didn't need a "plan" at all. Most rides were walk-on, and the FP rides were 5 minutes wait, so we just rode them then. We went on BTMMRR twice in a row with no wait! So it's not worth it if you're going on a low-peak day.
However, if the Sunday thing doesn't bother you, and you're going in peak season, I highly recommend it. It's personalized just for you.