IMO, if bothering the user at all, you should limit the number of options to two. E.g., after finishing a certain process like submitting an order, you can ask

IMO, if bothering the user at all, you should limit the number of options to two. E.g., after finishing a certain process like submitting an order, you can ask the user "Do you like our website? YES / NO". If NO, then you can take them to another form so they can complain with details. Having choices 1-10 is way too granular (we're not trying to get Yelp ratings). And popping up on the screen makes me want to leave the site. On the positive side, I have had pleasure of using some well-designed interfaces, and the giving of positive feedback probably reinforced in my mind that I liked the site. I.e., it made me cognizant of the good design.