Well, I used AirBnB in the past and have only good things to say about it, until I tried to find a short-term (month) stay in a big US city. I noticed that more and more people are using AirBnB to advertise their more expensive daily/weekly stays instead of posting to craigslist with a monthly stay. So the middle ground (monthly) is also being disrupted, not sure if I'm happy about it now :)