I don't have 'issues' with Mexico City. I'm just being honest with the OP who asked the question. Telling an already naive person to go there with a bunch of other guys looking to get boozed up and not worry is just flat crazy.

I've been there several times and Toluca (worse).

I was shocked at how bad it was and I've been to some other really impoverished places on the planet. Mexico City is only second to a few cities I've been to in mainland China (for pollution) and probably the worst for an overwhelming feeling of not being safe. I'd probably give a tie to Sao Paulo but they are both bad.

I don't know anyone that would go to Mexico City for fun. Go to one of the 'Americanized' (<---read artificial for Yankees/Europeans) like Cancun or Cozumel or whatever if you want to have a good and relatively safe time.

BTW, I've never had to worry about drinking bottled water anywhere in the US either. That should generally tell you something about a place.