I've been riding a burton joystick the last two seasons. I'm not a fan of the channel. I never found that I wanted to change my stance on the fly and I would have to tighten it every time I went up. If I forgot to tighten it my binding would loosen up and it would feel super sketchy.. And I'm only 5'10" 155 lbs.
But I actually just picked up the Ultra dream (158) today! I read some good reviews and went to a ski convention and talked to a bunch of people. The guy that sold me on the ultra dream had just bought one himself. He hadn't ridden it yet but had talked with a K2 rep. The rep said it was the board a lot of K2 employees were using as their go-to, everyday board.
One detail that stuck out for me was the rocker on the tips. I was told that because it's a fairly dramatic curve the edge contact is further back from the front of the board. So it rides shorter in terms of responsiveness, but still floats like the longer board it is.
I haven't ridden it yet, so I can't speak from experience. Hopefully I made a good choice!