The Arbor House is located on the near west side, right across the street from the Arboretum. The owners are very much into "green" living and have set up an environmentally correct guest house. All building materials in the Arbor House as well as furnishings were chosen from environmentally friendly sources. There are two big drawbacks to the place: First, it is located on a busy street which can be noisy during morning rush hour. Second, it is too far away from the downtown area to walk so a car is a must. Both of these facts take away from a pretty nice idea. My experience with the owners is also a minus. They are a bit pretentious, using their environmental "awareness" as a cudgel to guests and others interested in their establishment.
If you choose to stay there, request the new building that is detatched from the original. It gives you more privacy than the main house. If I wanted to visit Madison for a short stay, I would prefer to stay in a downtown hotel like the Concourse or the newly built Hilton.