The bus arrival time is a just a little off, which can have a multiplier effect. I took the bus, which I thought was arriving soon, which ended up being slower than walking. Then I missed a train and have to wait 8 minutes. This might make me take a later connecting train. So instead of being early I might be late for work.
Otherwise, when it works, its great.
Brody23&45 about Moovit: Live Transit App - Bus, Train & Subway, v5.5.2