The 5 stands out from our others becasue it is the only knife we use 1/4" thick steel to make as spec'ed by the SERE folks. And I personally don't carry it because of the weight. I do have one in the truck for an emergency like breaking car glass . But sales are definitely not slow on the 5. It is all we can do to keep up with demand and sometimes we fall behind on that
I like my 5 but probably go with the 6 more due to the weight of the 5. Both are great. I like the weight and balance of the 6 more. However, the 5 for its size is well balnced too. I think it is a personal preference but I think the 6 is a more versitile and easier to carry.