I'm thinking about getting one but i'm not sure which to get. :/

My recommendation is The Evil Within.

But the question is how much stealth you like in a game. I don't enjoy being stealthy that much, so Alien got boring very fast, there are only so many vents I can crawl through before it gets boring. To me that happened in chapter 4. I don't think I will ever get back to it.

I hear nothing but good things about The Evil Within. My buddy at work absolutely loves it.

Well, in my opinion, you should pick up The Evil Within. It has a good Resident Evil vibe; a bit rough and unpolished around the edges, but the content itself is gratifying.

If you're in the mood for a Condemned-type more of an adventure, mixed with stealth, choose Alien: Isolation, then.

I've heard that both are great but Alien has a very kind of gameplay; it probably has more in common with Amnesia than Silent Hill.
If you're into more traditional games; get The Evil Within, of you want to try something else, get Alien: Isolation.

I think you should pick The Evil Within, it's great game in my opinion.

About that Alien Isolation, I loved the game but this is not for the most people(sadly i'm not one of them), I heard people played this game then got bored quickly.

Buy Alien: Isolation only if you're a hardcore Alien fan. If you are, then but it, but if you're not, buy The Evil Within.

The Evil Within no doubt! the game is so awesome the reviewers can suck it

Horror at it's best IMO

Bayonetta 2