We were in the parks 4/3 and 4/4.
4/3 we did early entry for MK, rode Space, Buzz, Peter Pan. Went over toward BTMRR to ride when it opened at 9am. Rode it a few times and then Splash once with hardly any waits (maybe 15-20). Then went to Fantasyland to walk around and take pics of the new area and eat lunch in the castle at 11 am. Felt like we got a lot done that morning. Hopped to AK and rode Mt. Everest Single several times with a fairly long single line, probably 10-20 most rides (rode 5 times). Dinosaur was about 30 minutes.
Back to MK for FP+ on Space around 4:30, Belle's Tales, and BTMRR -- all our FP+ wait times were short. We rode BTMRR again standby (20ish minutes) rode Pirates and HM, very short waits. Had no trouble finding a spot on main street for the electric parade.
Friday at Epcot was another story. 9:15 we arrive to find the soaring line time jump from 30 to 90 minutes while we are standing in it. Thankfully it really only took 45. We walk over to Test Track, 110 minues with singles being 30. Yes, it took 30 to ride via single. Took a good 20+ to ride again that night around 8:30 pm via singles. We hop over to Studios to use our FP+ for Star Tours (not needed, practically walk on, we ride 3 times), Toy story, and Tower of Terror (we ride again via standby 20 mins). Rock N Roller coaster had long lines, 60 mins, and the singles took a good 30 so we only rode once.
I found spring break to be busier than fall. I'm not sure if FP+ had anything to do with it as I've not been during spring before. I also found that there are a lot of middle and high school groups so the thrill rides tended to get these huge groups of kids in line.