If you want an honest critique of your image or portfolio, ask someone you know and trust. You'll rarely get a fair or unbiased answer from the community. When a model asks for critique, she will often face a queue of photographers who, if interested in working with her, will provide positive feedback, and if not, may give a negative review simply because they’re not interested in working with her. If a photographer asks for feedback, they are likely to be met by a slew of 'the best photographers in the world,' eager to give advice—even if they themselves haven’t quite managed to get the camera off manual mode in the 30 years they've been shooting.
Bottom line: a review or critique only has real value if you trust and respect the person giving it, and if it helps you progress as an artist. Otherwise, most of the time, you're just setting yourself up in a shooting gallery—and not the nice kind with shiny cameras.
I have a few people I talk to regularly on here whom I trust, and I often share my work with them because they give me honest answers and feedback I can rely on. I’d rather do that than throw myself into mob rule controlled by clique bias and self-adulation :-) Just saying.