Personally, I'm a little ...um... cheap to pay for critique. I value my critique group intensely and find they really give me what I need whenever I have doubts about a piece. However, I was once asked to try a number of different professional critiques and write my opinion, so I have had paid critiques done. I find them very uneven. For the sake of evaluation I submitted pieces that had clear problems that were relatively easy to spot. Of all the paid critiques I had done, only one really seemed to catch most of the problems. In one instance, the person assigned to do the critique worked in a very different area of children's writing and really had no idea how to approach the piece I submitted -- some of her advice would have actually made it harder to sell the piece. Only one of the critiques offered any market-slanted advice, meaning only one of them really looked at the piece in terms of actually selling it to a publisher. One of the pieces I submitted was actually unpublishable -- it had a premise that simply would not sell in today's children's market -- period. And not one of the critiquers told me that. To me, that's a fatal flaw. It's nice to help a writer make the piece better writing but if there is no way to make it a marketable STORY, the critiquer should tell you that -- it's only fair.
So, overall, I was underwhelmed. If you DO decide to pay for a critique
* try to get a critique person with some experience in the area you are writing. (A writer of 12 nonfiction books for young children may not have a lot of valuable advice for a writer of an edgy YA novel.).
* ask for specific advice about markets. It's possible they would have told me if I had asked. I don't know but I think you have to make them aware that ultimately you would like to be published and you want to know if you should pursue that with this specific piece.
* weigh the advice carefully. Consider all of it but if it feels really wrong (after you've given your ego time to cool off -- all advice sounds wrong to me on first read, I had a rather obnoxious writer's ego) it may be really wrong. Don't try to do something that feels totally wrong for you because odds are it will come across forced and uneven.
* save all drafts. You can edit yourself to death trying to follow everyone's advice. If you get to the point where you have no idea where you are -- early drafts can help you retrace your steps to the point where you felt your work was going in the right direction.
That's my dime's worth.
gran