Mona: I am wearing the new $500 dress that I bought last week. How do I look?
Husband: Wow! You look great! I am going to be so proud taking you to the dance.
***
(At the hospital)
Martha: How are you feeling?
The Parser (in a hospital bed): Not bad!
Martha: Well, I think that you are looking great (if I compare your appearance with what you looked like when the ambulance brought you to the emergency room the other day.)
With those verbs that refer to the way somebody or something appears to our senses, look, sound, feel, there appears to be little real difference in meaning between the simple and the progressive forms. The same is true, to a lesser extent, of smell and taste.
Usage is changing. When I started teaching, over forty years ago, the progressive forms were rare.