Pesonally, I look for the artist to mention that they welcome criticism before giving any. Of course, by that same token, I refuse to give any rating or comments on those that do not. After all, if they don't want criticism, they must not want kudos either right? ;) I am a hobbyist myself, but when I do get around to putting an image up (only have 2 left up right now) I ask for honest input.. not only to improve my abilities, but to get others viewing my pieces to think for themselves 'how would I have done this better if it were my work?' Frankly, if you don't want criticism, don't allow it. That's why the check is there for "allow comments."