There is NO scientific way of rating anything here, it all depends on whims and fancies of the writer. However as a general guideline, when we give a particular score (out of 5) to an outlet, we mean this :

5 – Mind Boggling, everything works

4.5 – Super awesome, Perfect example of food

4 – Excellent, worth making an excursion now..

3.5 – Very Good, Recommended..

3 – Good Food, try it if you are in area

2.5 – There is something positive about it, but…

2 –  Would only eat if I have no other option..

1.5 – Would only eat if I have no other option, but I must be dieing of hunger.

1 – Okay, after all its food. it cannot get lower than, unless it kills me.