I would prefer to sleep late, but when WDW has crowds, it is so much better to get to the park at opening. We tried it both ways last week. We were tired from traveling so we slept in our first full day, and then spent a lot of time in line. The next three mornings we were at the parks at or near opening and it made a huge difference in what we were able to do. The only way the early plan works for us is to leave the park by 1:30 for an afternoon break -- I'm happy to leave those crowds behind!