I use a full cheek copper snaffle on my boy.
What works best really depends on the horse. We have a couple horses that do fine on a hackamore, and some that need a shanked low port. I think I'm one of the few, other than another boarder, who rides a snaffle, but Hoover has always responded well for it. I see no reason to test him with others since he does will with it.
I like how gentle it is on him, and doesn't pinch. I also like that it tastes better for him than a regular bit. The full cheeks keep him from pulling his headstall into his mouth, which he will do when bored.
The only thing I don't like is that he plays with his bit a lot, but he has a very short attention span. I'm looking into getting him a full cheek copper snaffle with a French link roller from Mikmar for my birthday in August.
Obviously, I like the split. My instructor tends to prefer the solid, particularly the low ports. But as I said, it really depends on what the horse responds to. Hoover is soft, so I can use a gentle bit.
"Sit tall in the saddle, hold your head up high. Keep your eyes fixed where the trail meets the sky. And live like you ain't afraid to die...don't be scared, jut enjoy the ride." - Chris LeDoux