Works well and the map view is great and can be used offline unless you zoom in too far. The critical problem is that the direction of travel is wrong , so go to the opposite platform from what the app says. It's not a problem to check the station list as you go to the platform. Other than this silly mistake the app works very well.
Going the wrong direction I have been using this app during a week now and it consistently more than once a day gets the wrong direction of travel. It gets the metro stop name right but double check direction of travel. Uninstalling!
wrong platform have used it 3 times in our recent trip and we end up in the opposite direction.