For what it's worth, we went during Wine and Dine weekend for a 3 day trip, and the only reason we were able to do everything we did was because of the FP+ system. We did the Expo, rolled into AK at like 11am, changed our FP+ times from later in the afternoon to late morning (we arrived earlier than we thought), and we did our core rides before rolling to EPCOT and enjoying the afternoon there.
We did rope drop at MK and with the 3 FP+ we had, we didn't have to run all over the earth to get the paper FP or wait for times to open up. We walked on to everything at Fantasyland and HM, then we did Splash, Space, and Thunder and were back at the hotel for our pre-race nap at 2pm. The last day, we walked onto Soarin, then did the FP+ for it later and didn't even use the FP+ for Nemo or Spaceship Earth we had.
I was prepared to hate it and rely only on paper passes, but honestly, we pulled one paper pass and didn't even use it.
My sister went Thanksgiving week and also planned on hating the FP+, but she had a similar experience.
We're going for PHM and I'm nervous about using no paper passes, but I'm fairly confident it'll work out... Just having that safety net of paper passes gone, it's nerve wracking. I just wish we could, if we bought PH's, get passes for multiple parks. Right now I see little value in having a PH, though that said, I guess when we do, we only really pull passes for one park and not all we visit... All the headliner FP slots are long gone by the time we hit the second park, unless we get randomly blessed by somebody.