Mark's place is a gem. My girlfriend and I really enjoyed the space, which is perfect for a couple staying the weekend. Here are the things we liked:
1) Mark is communicative and transparent. He was ready for us when we checked in and he gave us instructions when we checked out. The process was easy and we didn't have to think much. He also gave us a ton of recommendations for places to check out, with thorough descriptions of each -- a nice touch for sure!
2) The apartment has cool furniture, the layout is well conceived, and it's pretty hip.
3) Logan Square is a cool spot, close to a lot of good restaurants and coffee, and reasonably close to public transportation.
All in all, not much to complain about. I guess our only complaint would be the sometimes terribly cold Chicago weather. But Mark's place does stay pretty warm!