I clicker train Dusty. I trained Dixie with positive reinforcement but not with a clicker. Dusty is learning so much faster than Dixie did and more accurately. The theory behind clicker training is to teach the behavior. You eventually need to phase out the clicker when the behavior is shaped.

As for carrying it around with you, I don't. While I am shaping the behavior I want the dog to give, I only work the dog under controlled circumstances. You do not want to send mixed signals. Dusty is worked twice a day for 10 minutes each session. I do it before breakfast and dinner and I use his kibble so he doesn't get too much extra food to pack on unwanted pounds. At training class I use special treats such as cheese or boiled chicken.

The nice thing about clicker training is that the behavior is enforced quicker. While you give a verbal and a treat, there may be a few seconds between the behavior and the reward. With clickers, the sound is instant and you have a few seconds to pass on the treat.