Don't really understand how you measure value over there

im saying since im getting it for free shouldn't i go for the more expensive one?

You can choose between a lot of gameplay from DS (up to 40 hours) or little from AW (up to 7-9), so value would be the angle at which you look at it. But go with whatever you want, if you feel like playing AW just now, get it. DS can wait, unless you have to choose only one game period, than go with DS as it's a much more enjoyable experience.

I've clocked more than 200 hours in Demon's Souls. Of course, I have Platinumed it twice >_<

is it really that challenging though. how long did it take to understand the rhythm of the game? How many times do you expect me to die before i understand it?

To get the grip of the game, I spent ~10  - 20 hours (depends on the starting class of your character - rogues are the easiest, mages by far the hardest, i started with a mage, as usual) . Basically, as soon as you get to beat Iron Knight. You'll die countless times until you get to finish the game though.

I haven't played Demon's Souls, but Alan Wake is good if you want an absolutely GORGEOUS game. It's one of the best looking console games I've played, and easily the best 360 game. The gameplay is kinda average quality, nothing special. The story is good, but nothing to write home about. 

Take that as you will.

You should go for Alan Wake simply because the kind of person who knows he wants Demons Souls would get it automatically and everyone else will probably hate it.

By both, live now, regret later.

Spell right first time, never regret.

Buy.