I was just wondering what mouthpiece is better I own a conn helleberg 7b and a deg 24aw I only use the helleberg but are there better brands and also what is the difference between 7b and s?

None are better. I've seen people prefer Kelly plastic mouthpieces over expensive artist models. These weren't pro players, duhhh, but the point still stands. The mouthpiece that's the best is the one that

A.) works best for you
B.) works best with your instrument.

So you can't necessarily go by asking "what's the best?", rather you have to go out and try a bunch and figure out what works specifically for you and the instrument you intend to play on.