The wait time can vary from as little as 1.5 hours to as long as 5 hours after you land, for your bags to arrive at your room. Disney calculates the wait time from when you check in with Magical Express and ends when your baggage arrives at your hotel. Last October we arrived at MCO at 6:30 PM and our bags arrived at our room at Midnight. We were told that bell service was extremely overwhelmed that night. Last January we arrived at 11:30 am, went to play golf and everything was there when we returned. It was very smooth. The best advice is to bring a travel bag with you that has the things you need right away. I'm flying in again this May and will be arriving again around 6:30, I'll bring my clothes for the overnight with me.
By the way, the return trip is great, drop your bags off in the morning, and you don't see them again until you arrive at your home airport.