Just came back from Tokyo. Tokyo's public transportation is awesome. You do also need to walk a lot at times and the first few days our legs were quite sore. But towards the end of the trip I can feel my leg strength again, felt healthier, and did not miss my car at all. To go to certain places, you do have to plan a little bit ahead, for example, a day trip out to Mt. Fuji area requires booking tickets because right now there's a ton of tourists. But within the city, the subways are so convenient.