Izzy, we tried the flakes, too. Yep, they worked well, but the flint corner tang knife I left there worked even better. I think we processed three or four hogs and it never slowed down. I saw one nick out of the edge where I twisted it inside a joint. Flint doesn't bend too well.
On soft tissue, flint/chert/obsidian is pretty amazing. It's brittle nature, though, is something to be aware of. That what's makes it knappable, but also makes it vulnerable to damage from hard stuff. Can't have one without the other, I guess. At the same time, I've put stone and glass points through hog ribs, shields, and femurs and hardly saw any damage at all to the points. I spined a hog once, though, and the point really blew up. Killed the hog plenty dead, though...
McDave, about all I can say is that all knives are not created equal. There are several factors at play, like edge angle, type and quality of edge retouch, and size of the flakes.