I've heard some really mixed things about this game. Is it worth the buy? What else would you suggest?

(p.s. I've already got crisis core)

I've heard good things about Demon's Souls. Is it worth the difficulty?

I'm in the market for a really good PS3 RPG. So far, I've been looking at Fallout 3, Oblivion, and Dragon Age. Borderlands at this point, for me, is out of the question. I'd rather wait for it to go GoTY... unless it never does, then I'll pick it up later.

Out of those three, which would you suggest? If none of those are appealing to you, I'm open to suggestions. I want to make the best decision possible.