Well, I spent Nov 22-29 at WDW, and my experience with FP+ was mixed. I am a rope-dropper, so FP+ was great for my family later in the day once lines started to build. Keep in mind that I also was able to schedule mine before the tiers, and I think I would have felt less positively with the towering in place.
My main quarrel with the system is how buggy
MDE is and how difficult, or often impossible, it was to change a FP+ for any reason. The kiosks were not conveniently placed, and the app constantly crashed or wouldn't complete transactions... I
felt like I spent a lot of time of my phone on busy days and sometimes NEVER managed to change what I needed to. And if I couldn't change a FP+ because of MDE problems, and then the time passed, then I lost that FP slot for the day. So there were some days I only got one or two FP+ opportunities total because the app crashing prevented me from changing something when I needed to. That was incredibly frustrating and disappointing.
We stayed at POP, so we didn't have access to FP- to make up for the FP+ losses. It was annoying watching other people able to pull FP from the machines when we couldn't, knowing that we'd lost 1 or 2 of our only FP+ opportunities because of app problems. I probably could have gotten compensation with anytime paper FP from guest services if I had cared to make a big deal about it, but I decided to shrug it off and move on because I was tired of dealing with it. We just rode standby instead, which was actually not as big a deal as I thought it would be. I would have felt differently had crowds been heavier on those days, which luckily they weren't.
On the other hand, on the days on which I didn't need to change anything, and I stuck with my original plan, I had no complaints. FP+ lines were not long, and I never waited more than around 10 minutes or so. Sometimes the lines LOOKED long when you walked up because of the rate of MB scanning, but then once you were scanned you could just walk right through and practically get on the ride within a few minutes. So the lines might look long to passers-by, but really they weren't bad. I also found CM's to be very efficient and accommodating.
As for standby lines, until the parks became very crowded on Wed and Thurs, they were not bad at all. Rarely more than 30 minutes, usually more like 10 or less. I didn't find it prohibitive, and we did much of our riding without FP with the exceptions of a couple of headliners.
I realize that YMMV, and even with the MDE frustrations, my family still had a wonderful trip. I do think that the tiers are a terrible idea, but I am not opposed to FP+ in general. I just think Disney needs to first of all work out the MDE bugs, and then they need to forget the tiers, and finally be consistent with what they allow guests to have. I hated that our resort choice prevented us from enjoying the same privileges as all other guests, especially with the FP+ change/loss problems I experienced. I had to make a conscious choice to go with the flow and decided that I would set an example for my kids by having a good attitude regardless of my frustrations, and the result was more good than bad, no doubt. But that's because I chose to make it that way, not because Disney made it easy on me! Lol!
However, I do think I will be waiting to plan another Disney vacation until they work out some of the problems with the system and decide exactly where they want to go with FP+ in general. This is obviously a rough patch for WDW at many levels, and I hope they are able to work out a compromise between FP+ and FP- so that a backup exists for guests when the technology fails them.