Several of the responses tend to prove my point about grade inflation - the idea that anything less than 5* is "bad" or will ruin people. That should not be so.
When everyone is 5* it is a completely unbalanced scale. Then the maximum is average, and there is no way to identify above average or exceptional performance.
To my mind 3* should be perfectly OK - a good experience, good service, and that would be an average mark.
If the grading scale is 1 to 5 stars, then I think of the scale as follows:
* Fails to deliver, or poor experience, avoid.
** Lacks frills, but delivers.
*** Solid experience.
**** Above average in several aspects
***** Exceptional experience in most aspects. Nothing average.