I couldn't quite give this place 5 stars but would have done 4.5 if that was possible but wasn't so 4 stars it is.
First the bad: Despite what the host says in her description of the property the train is VERY LOUD! The tracks are about 30 yards from the apartment and a train goes by around every 6-8 minutes, 24 hours a day. The noise machine provided only helps with people walking on the sidewalk making noise which they did starting at around 5:30 each morning. My view is that the host downplays the level of noise too much and a more accurate picture of this issue would be in order to future potential guests. She lists quiet time as between 10:30 pm and 8:30 am but in addition to the train noise, the tenant upstairs made noise until late at night, midnight one night during my stay. He has a dog that can be heard running back and forth (no barking though). I'm not sure it's that he's excessively noisy as thin walls/ceilings are to blame. The quiet time period listed is unreliable at best.
There was also construction going on at the adjacent building starting at 7:00 am but this didn't figure in to my rating as it was presumed the host had no control over it. The walkway between the two buildings is about 4 feet wide and the workers were using the walkway which is right outside one of the bedrooms so sleeping in was impossible.
Despite sending the host my arrival time in to O'Hare and texting her when I had left the airport on my way to the apartment, I stood on the sidewalk for over 20 minutes waiting for her to arrive and check me in. In spite of her telling me she lived only a mile away.
Now the good: This is a very nice, clean apartment with just about everything you need provided. There is a "Just In Case" basket that has little things like snacks, umbrellas, etc just in case you forgot to bring something. The location is very good but there is a medical center across the street that also provides additional noise.
The host was very good about checking with me during my stay to see if everything was ok. I did mention the upstairs noise to her but she didn't say whether she'd address it or not. It was still noisy from upstairs after that so I'm guessing not.
This place is priced well but there are downsides to it especially if you like quiet or unless you are a dead to the world sleeper. Given the price charged for a stay I would say this should be classified as you get what you pay for.