I can't say enough good things about Mark's place! The location was absolute top notch, just a 5 minute walk from the L and a stone's throw from a bus stop. My husband and I enjoyed the clean, spacious interior and slept like babies on the soft and cozy bed. The heated floors weren't really needed for our mid-October trip, but they were luxurious nonetheless and probably very nice in the dead of winter. Mark's local suggestions were great, but we would also highly recommend visiting Dinkel's Bakery during your stay. It's a short walk away and had the absolute best cakes, cookies, danishes, and donuts in Chicago.
All in all, a fantastic, lively, clean, safe place to stay for your Chicago adventure :)