The game is never frustratingly difficult. Everything in the game is very deliberately designed, never unfair and when the game beats the player down, it's always clear why it was the players fault. You see, a player's impatience in Dark Souls is the only thing that will get him/her killed. But dying is never the result of the player failing at Dark Souls, it's simply part of the process of learning Dark Souls and absolutely integral to the game.
Dark Souls is learning to play with more caution than is normally necessary in a modern video game, learning that with every step comes greater risk, learning that with patience comes great rewards. I've found few games are capable of conjuring the kind of genuine peril and dread that Dark Souls does. Even fewer games are capable of conjuring the pure elation you'll feel when you come out on top.
You have to play Dark Souls to truly understand the appeal of Dark Souls. It's an enigma and utterly absorbing gaming because of all of that and so far, my personal GOTY. I guess you could go watch the Giant Bomb quick look to get a little taste of it and read the article linked below too.
Giant Bomb Quick Look - Dark Souls
Dark Souls isn't broken - you are