Whether I like the scent or not is my main factor.
Then longevity, sillage, along with uniqueness. Uniqueness can actually score extra points for me.
Also, how well executed a scent is, whether or not it is complex, can not only earn points but also respect for the perfumer.
Versatility, wearablity, and concentration have little to do with how I rate a scent.
Value can, but only if it is exceptional.
Those are the things that matter to me, but I think you may find that different factors are of differing importance to different people.
BTW, Welcome to Basenotes.