Check raising allows you to get a little more info (although not alot) about your opponents hand. I'll often Check raise when i call a raise with something like 77 and the board comes something like 1092 rainbow. I've missed my set, but most of the time the guy will be on overcards, so i likely have the best hand. So i check raise, and they usually fold. You get called or re-raised and you are almost always beat. But because Check Raising suggests that your hand is very strong, you will always know where you are at with your hand.