It's so sad to hear how many issues everyone is having with their magic bands & MDE. When my son & I stayed at AKL last October, it all worked perfectly.
We had two 5 day PH that I received as part of the
DVC signing bonus. I linked those to MDE & was able to make my FP+ reservations for all 8 days of our stay, even though the tickets were for 5. It did make it a little harder for guest services to upgrade my tickets. They had to take them off of the magic bands, change them to 8 days & then put them back on the bands. But, even that only took 10 minutes or so. And taking the tickets off the bands, did not mess up any of our FP+ selections.
As far as I know, both bands worked to open our room the entire trip. I say as far as I know because I didn't get to use mine much. My son thought it was so neat, that he would race ahead of me in the hall, so that he could use his band to open the door each time.
We had the Deluxe DP & the bands always worked to use our meal credits. Although some of the servers did seem confused about how to scan & apply the credit using the handheld scanners they're now given. But, they all seemed to figure it out in the end. When using our snack credits, I sometimes had to scan the band more than once for it to process, but the CM's all seemed to attribute that to a problem with the touchpoint scanners at the registers. In fact there was a very strong concensus from them that the touchpoint scanners weren't very reliable, even when I was swiping a credite card on them. I can't really comment on using the magic band to make purchases. I prefer to use my credit card for all purchases, so I can log into my account & check my spending as I go.
As for MDE, other than being slow I was always able to use it ok. Certain things seem way easier using the app, rather than my PC. For example, I preferred booking dining reservations on the PC & FP+ on the app. But, both would work for each in a pinch.
I even found that I like FP+, when I was pretty sure I was going to hate it. Since we eat at almost exclusively at TS, I had to make my dining reservations 180 days out anyways. Knowing where we would be at one time of day made it pretty easy to book FP+ ahead of time too. I found that all in all, we did so much less backtracking around the parks than we used to. And my feet were so thankful for that! Plus, if we got to an attraction with our FP+, only to find the standby time was really short, it was super easy to hop on my app & change that FP+ to something else.
Still, even though my experiences were great, I'm fearful for my trip this October. Hearing so many issues from everyone now.... It seems like the technology worked better when fewer people were testing it. And now that it's out there for everyone there are a lot more problems. I guess I'll just have to keep my fingers crossed & hope that most the bugs are worked out by October. And for everyone that's having a hard time right now, please try to hold out hope. When everything works as it should, this system really can make your trip, so much easier!