Tokyo has a great subway system (for the most part--there are locations that aren't that well served) and there's good train service between many moderate-sized cities in Japan. But my experience is that, once you get to a city outside of Tokyo, the public transportation options aren't great.
You don't need a car, but you won't be able to reach everything outside the cities. It's fine since everything you need is in the cities, and you would never run out of stuff to see, do, survive with. So "need" is a strong word, but certainly if you explore further out you will want a car.
Not really a bad experience but I was able to walk as a tourist to where I wanted to go because the areas were pretty centrally located. The one time I took a bus to somewhere--don't remember location--it wasn't that convenient.
Kyoto has a lot of buses, so maybe that’s where it was. I’ve found that they’re usually on time and not too crowded, but maybe you had a different experience.
