Demon's Souls is amazing, if you're willing to import the Hong Kong/English version of the game from Play Asia or something. It'll be re-published by Atlus (creators of the Shin Megami Tensei (Megaten) series) in about 5 or so months and released stateside through them. But waiting on that is almost not an option!
This is probably one of the greatest action-RPG titles i've played in awhile. Dauntingly difficult, yes. But a very fun learning experience. Also, the game is pretty dark in some areas as well, and kind of gives me a Shadow Hearts or Parasite Eve vibe in some cases. Sort of like a survival-horror. It's kind of a mix between Oblivion, Ninja Gaiden, and Devil May Cry. And no, is not a TB-RPG. It's entirely action-RPG. Like Fallout 3.
I highly suggest importing Demon's Souls. I dunno if there's gonna be any DLC for it, however. And if there is, the American marketplace PSN DLC will likely not work for the Asian-English version of the game. Only the English one. So you'll likely have to re-purchase the American version when the time comes in 5 or so months.
Or skip the DLC, based on how good/bad it is. If it even happens.
Either way, I highly suggest this game.
It's VERY difficult, yes. But VERY worth it in the end.