I don't know how the Beta Foo's work but there are a couple other writer's sites out there that I do have some experience with. Neither site 'requires' that you critique other's stories to earn critiques of your own. However, you get more and better (more concise and helpful) reviews if you reciprocate.

I've found that doing this also benefits you as a writer since it makes you specifically look at stories with an eye for plot and story lines.

Both sites will be very direct in their critiques so take your extra thick skin if you go there.    Theirs is the kind of help most authors are really looking for though, so I recommend them both.

Don't be put off by FanStory's appearance of requiring money for reviews. You can also earn FanStory dollars by reviewing other author's works. Also, fantasy-writers' acceptance is not immediate. I've never heard of them rejecting anyone, but it takes a day or so for an administrator to approve the request. Here are the links and have fun if you go. 

http://www.fanstory.com/index.jsp

http://www.fantasy-writers.org/