Easy communication with the host, clear and accurate instructions for arrival and departure.
The apartment is in a great location just blocks away from the blue line train, which has a direct route to O'Hare, as well as many great spots throughout the city. The neighborhood has tons of fantastic restaurants and bars within walking distance. The bar below the apartment, Spilt Milk, also was a nice spot to grab a drink after a long day -- great outdoor space and nice beer and liquor selection.
We chose this apartment for our stay having read recent reviews that said, though audible, the noise from the bar didn't disturb the apartment dwellers at night. I was surprised at how loud it was, and I did have a tough time sleeping. Upon looking at reviews further back, I saw that there had been this feedback. If you're a deep and easy sleeper, this may not be an issue for you, but should be considered.
The place also wasn't as clean as it could have been. The floors and bathroom could have used a spruce.
Aside from these few things, we had a great time in Chicago, and this was a very conveniently located launchpad for our trip.