I've found that they reduce the amount of bite, and in some situations can reduce the hold aswell. If your frame is too flexy, try a lightweight booster first. My brothers T-Lite was terrible, so I put an RB booster on, this actually made the brake hold and bite better, because the frame was so flexy that if you set the bite point so the blade was an inch from your middle finger, it would flex so much that the blade would hit your finger when you were just on the back wheel. It's still quite flexy compared to some I've tried, but it's just right. I find that if a brake is too stiff I get arm pump. Basically if your frame is stiff enough without, don't use one because it can make things worse. If you want one to protect the crossover, you can make a protecter type thing or just get a braided crossover.