I like to see a member's "credentials" when they offer advice on an image.
If someone says they would prefer the background to have more/less blur (artisitic) or that in their opinion the highlights on the forehead are blown (whether you intended to do so or not) I fail to see what their 'credentials'' has to do with it. It may just mean they have a different artistic view to you.
I remember reading a book by one of Britain's leading wine writiers and she made a point of saying that wine tasters are trained to recognise and (more importantly) explain and describe a wine; but whether a wine was 'better' is purely a matter of personal taste and in that respect anyone's opinion is as valid as theirs.
Critiquing an image is exactly the same.
If however they were trying to tell you how create a high-key image then their advice may justifiably be qualified by asking them to show an example