I have stayed in three different houses through Airbnb. I had different experiences in all of them. The first place was in Geneva, Switzerland. The apartment was filthy, in addition to the fact the hosts smoked inside the house all day long. The second was in Lausanne, Switzerland as well, and the place was dirty, noisy, and there were many hidden charges by the owner not mentioned at Airbnb. The third place was in Milano, Italy, and this one was really clean, and really nice, but the hosts was kind of rude. I think I ended up paying too much for the two first places I've stayed.
What I really disliked about Airbnb are their sneakiness for somethings: (1) I've had my review slightly changed once when I didn't use any vulgar language; I was simply criticizing the cleanness of the place I've stayed. (2) They bugged me for days to review one of the places I've stayed. In the end, they gave me a $25 dollars coupon to redeem in my next trip. Except that they sent me a coupon to expire in 24 hours!
I had enough of them that I even deleted my account!