Do you think that expression would be correct ? That point refers strictly to quality, and the expression "Ce n'est pas suffisant" refers to quantity.

Vous avez raison. Alors je dirais plutôt "Ce n'est pas assez bien :"

You're right. There is a grammar rule called "Espace insécable" that expresses the use of spaces before and after the punctuation marks (: ! ?). After reading your first comment, I decided to document myself.

Exactly, you're awesome! Why don't you post in French? :-)