Underworks is great, even if you don't have a credit card, which is good for those who go by paper instead of plastic. I got the 997 double panel, and I'm a size A, so they work well for me. I hear they work up to size B.
In terms of modifications/personal comments, I cut slits where belt loops match up on my pants, so (1) it doesn't roll up, and (2) my often baggy pants stay up without a belt. The only issue I get with this is that going to the bathroom takes one extra step, but if you're wearing a binder, you're already working for your appearance. Five seconds more isn't a major thing for me.
I've also found that it doesn't make your chest completely flat; it just kind of 'hardens' your chesticles. I saw today, though, that it doesn't matter with the shape so much. I met a friend of mine today I hadn't seen in a while while wearing the binder. When I lifted up my arm to catch my balance for a while (I was standing up), she was staring at my chest like one of my rats were crawling across my shirt. If your chest doesn't stick out, people tend to assume you're male, even if the shape is wrong. You can thank America's bad eating habits for that [moobs, muffintops, etc.] =] Even someone who KNEW I was female got confused, and I was only wearing that binder and a T-shirt. That tells you something.
