Tokyo vs Osaka ?

So, starting April I'll be doing my prep year in either Tokyo (at the University of Foreign Studies, to be exact), or Osaka. I will only find out where I'll go in March, so in the meantime I thought I would ask for some opinions about the two cities. Since I'll be there for a year, I'm personally more interested in differences related to lifestyle, like prices (though I belive both cities are among the most expensive ones in Japan), places to go, banks, services, etc. And of course if the people are different, because I only know the stereotype that "Osakans are more open and funny".
I'm also interested in how much "green" places they have and how easy it is to go for a little "walk in the nature"? The biggest city I lived in has a population of ~170,000 (3rd largest city in Hungary ), so I'll probably need a little break sometimes to just wander in a forest or near a river.
Right now, I don't really know what to answer if someone asked me which city I'd prefer. The only thing I could think of is that in Osaka I could learn Osaka-ben, and that if I do my prep year there I could still go to a University in or near Tokyo after that.

Osaka gaidai is located on a rather isolate mountain top so it's harder to get around.

Tokyo Gaidai is also far from the central, but you can still get around easily. All of my friends say that it's definite better to stay in Tokyo.

But if you want to save money a lot, Osaka gaidai is then better choice

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