Not much to say about these except they're awesome. You'd expect them to be though, right? I mean all they are is cedar shavings mixed with some kind of wax material. They light easily with a match or other open flame and burn hot for a long time. I forgot to start timing til they'd been burning for a bit but at least a good 15-20 minutes. I can't comment on how waterproof they are as I haven't tested that but they're wrapped in plastic. That should keep snow or rain off but the plastic has some small rips, etc.
If there's any knock on these things it's maybe the price. In the four-packs they're over two bucks each, although they're around a buck apiece if you buy them in larger quantities. Realistically, depending on how you're using them that might not be an issue. If you're using them to get a grill going or to light a camp fire I'd say 1/4 of a puck should suffice under most conditions. If you're trying to light wet wood then maybe you'll use the whole disc.
The long and the short is that I like these firestarters enough that I'll probably get a 36 pack soon.
havent tried it yet, just put 2 of them in my "Bug out bag" and gave 2 to my daughter for her bag. going by all the "Alone" type shows, cedar is the bomb. will be particularly interested in adding some pitch to one of these to see how that goes.