I haven't used airbnb -but, everyone I have spoken to is happy with it.
the time frame you mention is important - because many travellers only stop for a night or 2 or a week ------------ if you look up air bnb - it is important to put in the time frame that you intend to use because there will be one price for a few days and often/usually a massive discount for longer periods.
IMO - it would also depend on where you are going - I have used booking nothing in advance and heading into tourist bureaus in Europe - which worked really well - but, that was pre airbnb -
what I found was that you didn't have to take a punt with advance booking - you went in - had a choice of several places --- had a drive past and probably a look first - then booked - and often, if you stayed for longer times - got a substantial discount.
I have some bases in Europe that I will use again - that may not be airbnb - but, I will stay again because I know the people and the quality.
I would say at a guess that that system would work pretty much anywhere.
