I have been at Easter and August.
Easter is far busier with larger queues as its when everyone in the states gets holiday as well. In August, Orlando children are back at school by the 11th (this year) and others go back the week after.
We have just come back from 3 weeks, bad weather in the afternoons most days compared with less than 2 hours rain during the whole of Easter a few years ago.
That said, my preference is August, use the extra hour in the mornings and get on the busy rides straight away, then use fast passes for those you don't get on.
Then later on, take it easy, have lunch, watch a parade or go back to your resort and get up early again the next day.
People on the plane said that the weather was the worst it has been this year, but when it was hot, it was pretty unbearable, especially if carrying the odd additional pound from those buffet breakfasts like myself. But before 12, it was o.k.
Final reason for August is that people's holidays are spread over 6-10 weeks for the summer (Scotland break in June for their school hols), so more chance of missing them. People like yourself and I can only go the same two weeks at Easter, and that is the same for millions of UK and US people. In addition, hotels had vacancies in August, but didn't when we went at Easter.