Knowles,
First, welcome to the site. I haven't been here long but I have grown to really enjoy the talk that gets posted here. They all seem to be good folks.
The LRH uses the plastic disk to hold the primer. The Mountaineer is designed to use a bare primer. This would be a matter of personal preference for you.
I have heard about "tighter tolerances" from post on this website. There are others much more knowledgable than me and I am sure they will post an explanation.
One thing that is really great about Knight is the are made in the USA. Same for Thompson Center. I tend to like to buy American whenever I can.
Have fun studying and choosing. Then enjoy the hunting.