I bought a Telcel SIM at the airport, which by the way you can't find any specific store at that sprawling mass. It feels more like a shopping mall without any posted maps and hundreds of shops. My Telcel plan was cheap, about 1GB for five bucks. Unfortunately it stopped working after two days and had to change to another carrier.
Also walked around with my DSLR in my bag. I was actually surprised how safe Condesa, Roma, Polanco felt. No issues walking around late at night. Centro is more chaotic, but still a good spot to wander. Just watch your stuff like you'd watch anywhere else in the US. A coworker had his laptop stolen from his bag at the airport, so know it's out there. Stick to the areas mentioned here and you'll be good as golden.
Also walked around with my DSLR in my bag. I was actually surprised how safe Condesa, Roma, Polanco felt. No issues walking around late at night. Centro is more chaotic, but still a good spot to wander. Just watch your stuff like you'd watch anywhere else in the US. A coworker had his laptop stolen from his bag at the airport, so know it's out there. Stick to the areas mentioned here and you'll be good as golden.