score:4
The score is given by the Oyster reviewer.
This seems to be the concept of the website:
Oyster is the only hotel site that sends special investigators to visit, photograph, review, and rate each hotel. We inspect in-person β just like your mother-in-law.
On their page about their so-called investigators, they say about their rating:
We Rate Hotels Fairly
Though our reviews are unabashedly honest, we are careful to evaluate each hotel within the context of its category.