Speaking for myself, I've never guaranteed anything. Even my "token challenges" can be very deadly if the players make the wrong decisions.
As far as answering your question, you obviously wouldn't want to play in a game that I have planned for my normal players. My players ask to be railroaded. My players want to be challenged only some of the time. My players can handle being beaten down, but don't want to die (sometimes, that is an unfortunate side-effect of adventuring that even I won't protect them from). My players wouldn't be a fit for you, at all.
With all of that said, it is still possible that both styles of play can be accomodated by the new rules, but it does seem that my style will be easier to do.
EDIT: I would like to add that when my players come crawling out of the rubble on their bellies, barely snatching victory from the jaws of defeat, they are happy. If they see that I've planned this sort of game, they do not react well (I suppose that they only want me to "mostly railroad them" and "somewhat challenge them" *shrug*). This is why I only provide such "real challenges" only once every couple sessions (and the real tough ones even less often). I just don't rely on resource depletion as a way to ramp up the challenge, because resource depletion usually has a negative effect on my games (to tie it back into this thread).