Unfortunately you shouldn't trust the reviews on Airbnb especially for "private rooms".
Having used Airbnb myself for "entire place" and "private rooms" (in LA mainly), a lot of those reviews are unreliable. Anything less than a five star is basically sub-standard for a host.
Case in point...I once had a friend write a five star review for a property; sent him a message on Facebook to ask him if the place was actually good. Response, "book elsewhere" lol - It wasn't that bad apparently, just wasn't as clean and there were better options closer downtown.
Guests feel the pressure to leave five star reviews because of the culture on the site and not to offend any host. Since you build a relationship with then often and don't want to inconvenience the host (at least from my point of view)
There were some great entire condos that were better than hotels which certainly deserved their five+ star reviews. There were also some unique "private rooms" in Singapore that was worth the experience. To gauge an Airbnb listing, really look at the listing information itself and the small hints in the reviews. (don't look at the stars, look at the comments and the enthusiasm)