Just used the Minnievan service last night. We were post 'Ohana/post Hallowishes fireworks on the beach, it was 10:45 and I did not want to deal with getting to the buses.
This is how it was explained to me/my experience so ymmv.
It's still new so a lot of CMs had no experience with it. It is being tested at certain resorts, among them, BC, YC and BWI. You download the app, and get a code from Guest Services at your hotel. Then you are ready to use. At Poly, one CM had just had a review of the procedure and was semi helpful. The concierge seemed more knowledgeable but he was busy, and the valet guys I was referred to did not know much at all.
When I used the app, I was offered several Lyft cars of varying capacities, all within about 9-12 minutes arrival time. When I chose "Minnievan", nothing happened. Not even an estimate of time. On may fourth try at requesting, I was assigned an ETA of 4 minutes for the Minnievan.
He arrived and I got a text for my Minnievan #: 'Your minivan #xx has arrived'. Driver was friendly and chatty, very Disney CM-like.
He explained that they only have 30 vans and it is being tested at a few resorts. So that is why I wasn't getting any results with multiple tries: there are simply not enough vans at peak times. The drivers are Disney CMs with at least one year Disney work experience and are paid a salary by Disney. They only use the Lyft app to schedule the pickups. He had been dropping someone off at GF and as soon as he finished his fare he was notified of my request for a pickup at the Poly.
I have used Uber as well and the lack of immediate response to my Minnievan request was confusing to me; now I know to wait a bit longer after popular events. However, if it is peak season after a peak event, you could be stuck waiting much longer than a few minutes. This problem will continue until they get more vans as the service seems to be very popular.
As someone mentioned, you don't have to worry about surge pricing as it is a $20 flat fee. As there were 5 in my party, it was worth it to me. I have had taxi drivers of varying abilities over the years, so the idea that I was getting a Disney CM as my driver was very appealing to me, as was the flat fee with no tip required. The downside is that, at peak times, you may have to wait awhile before a Minnievan can be dispatched to you.
I would use it again.