Everyone on this board thinks their own beard is heavy, but simple logic would indicate that most of them are wrong. Furthermore, heavy bearded guys really need sharp razors more than heavy razors which is why barbers abandoned their W&Bs barber's use choppers for dubl ducks and C-Mon's en masse. A heavy stiff razor helps disguise any flaws in the edge and shaving technique. And they're very popular among guys who think their beard is heavy (which is pretty much everybody). But there are a lot of posts in the archives from guys who discovered after a few years of experience that their "tough" beard didn't need a heavy razor after all, it needed a sharp blade and decent technique.
MP762 has just really put a big nail in the Hart coffin for me here. This makes complete sense to me and I probably could have saved a couple hours of my life if this had come to me earlier.