@itssynecdoche I would base this on cities rather than country. Edinburgh, London, Vienna, Prague all great public transport. Rural Scotland and remote parts of Whales not that well connected (some parts you'll find a bus come by once a day). Many cities in Germany have good connectivity. Austria is actually incredibly well connected, even throughout the Alps.
Surprisingly Dubai (for the size of the city and how ahead it is of most other places) doesn't have the most robust public transport network. One of the sites I wanted to visit (I don't remember which one exactly) I had to get off at the bust stop and walk for about 1 km to reach the place (in that wonderful Arabian Peninsula heat). I suppose everyone has cars there so public transport is less of a concern for most.
@itssynecdoche yes I think the metro is really good too. But it mostly connects the main areas/tourist places. Dubai is a very big city and I think it's the bus network between the the not so mainstream places and the metro stops that's infrequent.