Actually the game is getting far more Good to GREAT scores than mixed. There's only like 5 or 6 mixed scores out of about 23 reviews so far. I would venture to say that this game is going to be great for the most part.
Trust your instincts. If the game looks good and something you think you'll enjoy, go ahead and get the game. Reviews are simply to give people an idea what the game is going to be like and point out its pros and cons.
Lots of good information, like he says in the review, it has its flaws but it sticks to its roots which is a good thing and that stealth fans will love it. Shooter fans will enjoy it as well since you can run through and shoot,