We just returned on Wednesday. All I can say is that it was VERY hot and humid. I don't think we will do July again.
It was crowded, but, surprisingly, we didn't stand in any really long lines (we did not do MK, however). We were at Epcot last Friday afternoon and everything we did was practically a walk on. The only long line was for Test Track, but since I work for General Motors, I don't have to stand in that line.
We went to MGM last Saturday. We got there about 9:30 a.m. and stood in line for about 20 minutes for Tower of Terror. Rock'n Rollercoaster was not working that day. Great Movie ride was about 15 minute line. Millionnaire, Muppets and Backlot Tour were all walkons.
We had fun, but the heat was brutal.