My experience in Europe has been very hit-and-miss. AirBnB for the most part is as expensive as a hotel but without any of the guarantees or protections. And most of them seemed to be professional operations, with "Super Hosts" controlling 10 or more properties in the same city.

The locations are usually nice compared to a business hotel, but rarely special. The "local knowledge" is no better than that from Lonely Planet / Trip Advisor. And if something goes wrong then I have much less recourse than I do with a hotel. If the room is noisy or smelly, I can't simply get a resolution by talking nicely to the guy at the front desk.