Of all the photo critique sites on the web, I have to say photosig.com has to be the best by far. The focus on this site is critiquing. In fact, while most critique sites pat each other on the back and say good job, photoSIG is known for the brutal honesty you find from those critiquing.
Several years ago when I joined photoSIG and began submitting images there, I found that I was not as good as I thought. I was a professional photographer, however my images would get torn apart and not in a mean way, but in a very constructive way.
Being on photoSIG and submitting images does take thick skin, but it is also an extremely effective method of becoming a better photographer if you are willing to listen and take suggestions.
On a side note, I’d like to add that the members on photoSIG are for the most part extremely pleasant to interact with and try hard to be helpful to one another. It is truly the best on line photography community I have ever been a part of.
There are also forums available for members to participate in and reviews and article sections. It’s a pretty straightforward site but the benefits are tremendous in regards to photo critiquing. I would suggest if you join and participate, that you support the site by getting a paid membership. It gives you more benefits but most of all I think it is important to support great sites like this one.