Try to stay in a hotel located in Downtown Mexico City, nearby the Paseo de la Reforma, on the Zona Rosa. I made a reservation for Sheraton Suites Santa Fé, in a new business district which was not located near city center (and by the way was extremelly expensive!!!). I decided moving on the next day for a cheaper hotel downtown and found out this NH Hotel, which is excellently located and has a reasonable price. Try to avoid sleeping in the "Bosques de las Lomas" or "Santa Fe" districts...They are too far away and have nothing else than offices...The real taste of Mexico is in downtown...
I just got back from a four-night stay at NH Mexico City. The lobby looks newly redecorated and makes a decent first impression. However, once I stepped into the hallway of the 7th floor where my room was, I thought I was in a different hotel! An ugly and dated carpet lead the way to my equally dated and ugly room. The ceilings were low with several cracks. The beds were ultra firm (which I didn't mind) and the fixtures (light switches, bathroom mirror, etc) were crookedly attached to the walls. Overall the room (dingy and staid) was the complete opposite of the hotel lobby which exudes a modern and sleek feeling. I had gotten a great discount online and had read on this site to be aware that that this might afford me one of the pre-renovated rooms. I should have taken heed. I could have paid the extra $25US to upgrade to an "executive" room but wanted to deal as little as possible with the front desk. They were unhelpful and futzed up my reservation. I was locked out of my room the last night. When I got to the front desk I was told that I needed to present my room coupon by the same woman who checked me in and took my coupon. She said she never took it. Rather than argue, I went to the business center to print out the coupon again. The printer wouldn't print and the ladies at the business center had no clue why. I finally asked to use the computer they were using. Also, housekeeping had a tendency to knock as they opened the door to my room every morning at 8:30 AM. It served as great wake-up call but if you intend to sleep in be sure to put the "No Molestar" sign outside. My suggestion is: only stay at NH if you plan on getting an upgrade (although I haven't actually seen the upgraded rooms) and don't expect the best service. Otherwise, the location is central and enjoy the free internet stations in the very deceptively nice lobby.
Decent heated outdoor pool. Free internet in the lobby.