We've used it four times since they started and it's always worked just fine but the timing has varied greatly. The first time was at AoA, I had stopped by the desk to ask a question and she said our room would still be awhile (we arrived at 9am) but about ten minutes later we got the alert that our room was ready. The next time we drove down and we were just reaching Orlando when we got the text that our room was ready at CBR. It was about 10am. We never had to go to the main desk, which is especially great at CBR with the way things are laid out!
We were doing so great at that point, I was surprised last year when our plane landed at 10am and we hadn't heard anything from Pop. We dropped our bags off at the resort and hopped a bus to Epcot. We got a room notification right at 3pm. Never went to the desk. That was the night before our cruise. The night after our cruise we were at AKL and that was probably the worst experience I've ever had at Disney overall... but anyway, the cruise transfer had us at AKL awfully early and we had no choice in that but our room still was not ready until exactly 3:00 on the dot. ( Personally I think that people getting dropped off from a cruise transfer should get early priority for a room since you have to leave the ship super early and they bring you back on property immediately after that... it should be part of the whole package deal. But anyway..) That day was more frustrating because we didn't really have any plans and I was SO SEASICK (my sickness doesn't kick in until I'm off the boat, it's awful). I just wanted to go to bed! I was wondering after those two experiences, though, if they just don't release your room to you until 3, or if they still release them early if they are ready. Because my text the night before and after the cruise came at exactly 3.