If you stay in Roma or Polanco you'll be fine. Mexico City was a little too chaotic for my taste, but also had some really beautiful and cool neighborhoods and a must visit if you find yourself in the middle of Mexico. Uber runs here so that makes it easy to get around. It can be as cheap or expensive as you want it to be, a decent hostel will run you $15 - $20/night. I cook many of my meals and prefer to splurge at nice restaurants a few nights a week vs eating at cheap places for every meal