I depend highly on reviews just to let me know what's out there. That's how I knew Shadows of Mordor existed, had come out and, on the balance of reviews and comments to the reviews, didn't suck. Same for Dishonored awhile back. I got some good buys that way, games I really enjoyed and that I might never have heard of or thought they'd appeal to me.
I stick to Escapist reviews, though, rather than metacritic or IGNs. I find Escapist reviews address issues a bit more directly, and if they don't, the comment section will, in spades. IGN might mention issues but they'll be lost in the fluff piece (maybe that's changed, can't be arsed to find out). If I'm still undecided, I'll go see if Angry Joe has done a review. My main purpose in reading/watching reviews is to get a feel for the gameplay, the flaws, the type of story, and see if it has a chance of grabbing me. A negative review won't necessarily turn me off. I still bought Thief 4 - I know that's not the official name, but I am not calling it Thief, I played Thief before the millenium rolled around and it was awesome. But Thief 4 was okay, no buyer's regret. While a glowing review doesn't insure I'll get the game. Far Cry 3 got praised to the sky and even turned Yahtzee into a banana, but I never felt the urge to play it (possibly because I saw the trailer and realized there was not enough suspension of disbelief on the planet that could convince me or my character to risk life and limb and sanity in order to save those self-centered sky diving yahoos he called friends). 'Skyrim with guns' should have sold me, but then I just went and played Skyrim again for the nth time and had a good time and saved $60.
TL;DR: Reviews put games on my radar, but I only depend on them so far when it comes to actually deciding to buy.