It's an ordinal scale with arbitrary meaning. 4 doesn't mean its twice as good as a 2 star rating (there is no interval or ratio). It basically means 5 = all ok

It's an ordinal scale with arbitrary meaning. 4 doesn't mean its twice as good as a 2 star rating (there is no interval or ratio). It basically means 5 = all okay! 4 and below there were issues of varying subjective degrees.