I think there are two similar threads running, here’s my answer same as the other thread:
Unfortunately, I have to say that I am no longer a promoter of this service, though I wish I had better experiences to still support it.
Last year we used it while checking into POFQ. We walked right in, no line-up, rooms were ready and request of connecting rooms was granted. I was extremely happy with the service.
However, the next three check-ins did not go so well. My DF and DM went to POR last November, and when they got there, they were lined up at the online check-in forever, with only one CM working, while they watched everyone else in the regular check-in line pass through and numerous CMs working. Finally, they left the online check-in line and went through the regular check-in line.
Our trip this April included two check ins, one at POR, then for our second week at BC. At POR, we were second in line to one CM checking everyone in. The people ahead of us had a problem with their reservation and it took a while to resolve, then we got up there and our connecting room request was not granted, so it took forever to switch rooms. Meanwhile the line behind us had grown, yet everyone that we arrived with who went through the regular check-in line was done. There were approx 4 CMs at the regular line and again only one CM at the online check-in.
When we checked into the BC, we were helped right away, no waiting this time, however, our room request of connecting rooms was not granted so we had to wait while they changed rooms again.
I think online check-in is a great idea, but I don’t think Disney is prepared enough for it. I’m not sure that I would use it next time.