Django or Ruby on Rails, which one is better for web 2.0 heavy ajax app?
ROR has much better community activity. It's easier to learn without learning ruby (i do not recommend that way, but yes - you can write in ROR barely understanding ruby). 
About performance: ruby 1.8 was much slower than python. But maybe ruby 1.9 is faster. 
If you want to build smart ajax application and you understand javascript it does not matter which framework you will use. If not or you are lazy - ROR have some aid to ajax requests. Also take a note about django /admin/ :)
I want to build a heavy ajax web2.0 app and I don't have javascript, django or ruby on rails. I have some experience with python. I am not sure which one to choose. I have a backend database and have to run few queries for each page, no big deal. So, I am looking for a choice which is quite easy to learn and maintain in the future.
Thank you