Ive seen some pretty well thought thru for the size and dollars kits rated down because the guys doing the review were sitting on the rock they could have used to strike sparks with ... but had to resort to sacrificng their blade edge to get sparks instead .
a lot of survival is not about correct gear .. if you had the gear on hand at the time itd not *be* survival situation but merely a hiccup .. but about not freaking out and trying plan b , c , etc ... stones are not the best striker , but they are not the worst either .