Check out this post by Robert Lee Brewer, the Poetic Asides columnist for Writer's Digest On Handling Criticism and Critique Groups.
I found it useful to read his prespective. I remember when I joined my first writer's group and the stomach churning feeling before I submitted my work to be critiqued. I could have passed out right before I heard the comments. But I also remember that after about six months nothing negative anyone said really stung anymore. I had grown my writer's thick skin- and it felt like a badge of honor. I'm not saying it doesn't affect me to hear that something in my writing doesn't work but I now have the abilty to quickly move past that and get back to working to make the piece better.
I do recommend writer's group. But, like without anything else, it is all about finding the right fit for you.