So, this may be old info, so take it for what its worth. There are only a few companies that actually manufacture the firesteel material itself, so unless you are buying an LMF, or from a place like firesteel or goinggear, you may as well buy a few cheap ones that are obviously different, and are cheap(yes cheap) and see what you get.
I've had both good luck and bad in each case. Basically it seems that you can buy more robust and corrosion resistant steels which spark a little less, or ones that spark more, but are consequently more reactive. I buy my blanks from some rando in china, but the ones I need to rely on, I spend the little extra to get from someone with a reputation. I've gotten a couple from china that were very hard and had very little spark. I've also got a Gobspark that is a fantastic steel, but in the humidity where I am, its 1/3rd gone due to just corrosion. But I'll pay to buy another one when the time comes because its stuck to an ESEE firekit handle and that works really well for me.
Hope that helps you in your search, also the striker is 50% of the equasion, so get a good one, I like the carbide strikers that firesteel sells, but there are others. there is a lot better available than a bit of saw-blade, and most of the chineese strikers are too soft to work well.
