I had a great 10 day vacation at Ivan's place. It's probably the best location in Mexico City, a very short walk from many of the most vibrant neighbourhoods like Roma Norte and La Condesa, as well as a short bike ride (or longer but still manageable walk!) to neighbourhoods like the historic centre and posh Polanco, and the iconic and gorgeous Chapultepec Forest/Park with all its attractions. Do bring earplugs if you're a light sleeper - while there aren't any noisy bars/clubs *on* this street, there are lots *near* this street, and you will absolutely hear car alarms and drunk people shouting late at night despite being 3 floors up, but that's the price you pay for staying in such a central location, and it's nowhere near as bad as it could be - I slept fine.
The apartment itself is exactly as pictured - small but sensible for 1 or 2 people, and spotlessly clean. (It was even serviced halfway through my 10-day trip - a nice and rare surprise!) It's stylishly decorated with actual local art, and checkin and checkout were easy thanks to the 24h concierge located next door. Internet speed is excellent and reliable; you'd have no problem working remotely here (ask Ivan for help if it's not working).
My only critique: don't expect to be cooking here. While it's a beautiful galley kitchen with new appliances (a 6 burner gas stove?!) there are almost no kitchen tools. For example, there's a single somewhat blunt knife, but I never found a cutting board…there's no corkscrew for opening a bottle of wine…and while there's an oven, there's no baking sheet or dish that you could possibly *put* in the oven. So really, microwaving leftovers and making sandwiches is about as much as you should plan for here, or bring your own kitchen supplies from home. (That said, there's dozens of great and affordable restaurants within a 15 minute walk, so I wasn't too mad about this. It's just a shame to have a beautiful kitchen you can't cook in!)