The adventure model is the lower priced version without the adjustability of the higher end models. I would personally get the standard version, that adjustability is well worth the money. The company itself seems to be very helpful and shipped me a bunch of parts quickly when I needed them.
When you put one on at first, you will notice it rubs a little bit, but after a while you get used to it. It is a well designed piece of protective equipment, but I do not like how it opens on the side. Check out Troy Lee Designs, they make a jacket that seems to be made with the Leatt in mind.
As far as rumors of broken collar bones, I haven't had any issues with it either. I had a collision with another rider at 60 mph on the pavement and walked away fine. I've had other tip overs and crashes throughout the past year since I've owned it. I'd recommend buying one, you won't regret it.