We just returned from a 4/15 - 4/20 trip (stayed at CBR). Were in the parks on the following days:
Tuesday 4/15: Epcot
Wednesday 4/16: MK
Thursday 4/17: DHS
Friday 4/18: Epcot
Saturday 4/19: MK
Sunday 4/20: AK
I was bracing for the worst. This was my first trip during a holiday week ever, and I had heard horror stories. Also first FP+ experience, and same thing on rumors.
I have to say, unequivocally, it was my favorite WDW vacation ever. It was me, wife, son (7) and daughter (1). We didn't wait in a line longer than 15 minutes all week and did all the headliners (most multiple times) but for Tower of Terror. FP+ worked amazing - the sometimes long queue's you see leading up to a ride are usually due to a temporary ride stoppage or someone who tried to get on without actually having a FP+ reservation and the CM taking the time to explain the system to the confused would-be rider (Which in turn does hold up the flow). My wife and son were going to go on BTMRR using their FP+ and saw a line that backed up to the Splash Mountain bridge and then curled around a roped-queue before getting to the scanners and almost didn't do it - I encouraged them to, they got through that line in about 10 minutes and pretty much walked on right after. At the geyser where I was waiting in no more than 20 minutes after they first got on the line.
The weather was mild (too mild, IMO - I wanted SOME "hot"), the crowds were not noticably worse* than what I had experienced on previous summer trips when crowds are supposedly more in the 5-6 level range and our son had some of the most amazing "extras" I'd ever seen:
1. He and wife got selected out of the blue by a passing Alice and White Rabbit to ride the teacups - they weren't even on line!
2. He got selected to be Beast in Enchanted Tales with Belle
3. Had a swordfight with one of the cast members in the Pirates shop after he did Pirates League, with a large crowd around him taking video
4. He did the Jedi training academy and got to fight Maul instead of Vader, which was his definite preference
5. A friendly castmember gave him a light up mickey sword in Epcot before fireworks for no good reason other than he said he looked like he was having fun.
Really, just a great trip. I do wonder what happened with crowds and maybe its a cyclical thing, in that last year's were reported to be so bad that it scared folks away this year (and perhaps the counter will happen next year??).
*The one exception here was when we returned after our mid-day break on Weds to MK. You couldn't move in the Fantasyland-to-Liberty Square section. And then trying to get down Main Street to the Confectionary for a little treat before the Parade was insane - people went nuts on parade spots (when there were actually spots to be found, and we did, near the Liberty Belle). BUT, that morning MK opened at 7 - we didn't quite make rope drop, but from about 7:15 to 10:30, we did every attraction in Tomorrowland and Fantasyland, some multiple times (e.g., Buzz) with nobody in the park. So it was give and take that day.