Chella, I've seen the "natural" dressage where they ride with a hackamore.
Dee, Gunther doesn't mind the bit, he just hates to have contact with his face in general. If I ride him in a hackamore, which I do frequently, I still have to ride him with very loose reins. So people who get on that are used to controlling their horse 99% by the horses face, are screwed.
Alwaysbehind, we have messed around with alot of other bits to see what is best, and this is the one he's most happy with. Yes, he has his teeth done regularly.