i have used two Air bnb rooms and one Vacation Rentals By Owner apt this trip in italy but i must say that so far the apt shares have not been very comfortable as in order to use the kitchen one must sometimes feel like they are invading the space of the homeowner, especially since we tend to come in late at night
the **** apt i used in Paris was quite expensive but had more than enough space for the four of us who traveled and the location could not be beat, Place Vendome! was in an old Palace Hotel...we did lock ourselves out the first night since we did not really understand how the old key worked.
if you don't want a kitchen and just want the equivalent of a hotel room for less money, the shares are fine....but tiptoeing around not to disturb others has not been the best situation. saved a lot of money, though! check for air conditioning in this heat wave. bon voyage!!!