4 stars: I'm not sure what all the negativity is about, for me, the app has always mostly worked fine. But maybe that's because I mostly use Google maps for routes and this more for monitoring train arrivals and buying tickets. The latter of which actually does have a pretty unintuitive UI if you need to buy another ticket in the opposite direction shortly after the first. I initially didn't assume that
3 stars: It is very problematic with the tickets. I bought my new Jahreskarte a week ago and still nothing appears on the app, plus all previous payments (i.e. history) have disappeared. To make things worse, Wiener Linien hasn't even sent me the physical card... I have sent them 3 emails and no reply yet. [EDIT] After ~ 2 weeks it finally works. Still, not satisfied with responsiveness and communication.
3 stars: Needs improving. When you search for the starting location/destination and click on the ticket icon, it would be good if it populated the ticket form with starting location/destination. Also it would be good to add additional passengers stored in the app so that you don't have to type there names every time you purchase tickets, this would speed up purchases.
2 stars: To show your ticket in the app, you need to be logged in, however I repeatedly could not reach this login screen unless I was on WiFi, which is not always possible. When I had a 4G signal the screen would just hang. Very frustrating experience. It's totally unnecessary to do this to your us...