That's why I hate using UG. They don't give you any reasoning behind their best parks like Mike does.
courtesy of
http://www.touringplans.com/tp2/UG2_index.php?PageID=14
Data we use to determine the best days for each park include:
Actual wait time statistics gathered in the parks
Our own counting of guests in Disney's parks
Disney's Extra Magic Hours schedule
Special events calendars
U.S. legal holidays
Outside sources (e.g., the U.S. Department of Transportation, Consumer Reports, etc.)
Some of these data, such as historical park hours, Disney's Extra Magic Hours schedule, and U.S. legal holidays, are widely available on the Internet. Other data, such as public school schedules, are available, but not from a single source (we had to look up each school's calendar individually). The more detailed data, including hotel occupancy rates and government statistics, require not only access, but fairly sophisticated analysis. And some data, such as wait times, we had to get ourselves.
I was wondering why Touring Plans recommends the MK for Mondays. I've always seen that as a bad day for the MK b/c everyone goes there at the beginning of their vacation.
Avoid MK on Mondays tip went out of the rotation several years ago (b/c it was not really good advice), now you pretty much only find that kind of advice in questionable guidebooks or official ones, like Birnbaums.
FWIW we use Touring plans and have always had great success w/ the crowd calendar being accurate and the Best Days/Worst Days have always been spot on. We even did out own experiments last trip to test the recomendations and have decided to exclusively use thier recommendations from now on out.