Karen's place is outstanding. In terms of location, it is in a very quiet, leafy street of a gorgeous Chicago neighborhood, with good access to restaurants/bars and the train nevertheless. While not in Downtown/the Loop, it can be a great option even if you plan to visit those locations.
The lodging itself is roomy, spotless, well-appointed, very comfortable, and has all the conveniences that you can possibly wish. The pictures don't lie: the decor is tastefully put together and will definitely make you want to spend more time in here just relaxing—no matter how exciting Chicago is.
Karen was a kind host and very quick in terms of communication. The few questions that we had (regarding parking and keys) were answered quickly, clearly, and accurately.
I have visited Chicago a handful of times and this lodging definitely stands out in a city where it's not always easy to find a place. Strongly recommended.