If I played Ground Zeros (I'm never playing another MGS, Kojima's cash grabbing has gone too far) I would have scored it the same for the same reasons, I thought the very little gameplay in MGS4 was great but I can't give it anything over a 6/10 due a very short length (4 hours) and cash grabbing multiplayer.
I find that with Angry Joe, the score doesn't tell everything. Listen to what he says, as he dissects the game almost entirely. In his recent Ground Zeroes review, he gave the game a 5 out of 10. Why? Poor length. He says what his says, and I find myself mostly agreeing with him. And let's face it, Sleeping Dogs wasn't anything groundbreaking. That game's mechanics and gameplay was average. Nothing bad, nothing good.
I should have made the topic title 'Do you let game reviews impact your decision' because I myself still watch them to get an idea about what a game is about, but I don't let them impact my choice to buy a game or not, I stopped doing that entirety (I never did it fully) after I saw this.
I like to watch Angry Joe's reviews because sometimes because they are funny, but at the end of the day, he is another mainstream critic sadly (he gave Mass Effect 2 a 9 and then only gave Sleeping Dogs a 6 saying it was average and nothing special for example).
And I though Sleeping Dogs had the best combat out of any open world game and the setting was both unique (finally a sandbox game set outside of the USA) and lively, Mass Effect 2 on the other hand was nothing special and I'm sure no one can say it is without mentioning the words (or any similar words for that matter) 'story' or 'characters'.
Just an advice - when you review a game like Sleeping Dogs, you don't generally compare it to other games in the same genre. You look at it from a general point of view. Of course, it has the good fighting and such, but it's good compared to the other open-world games. There are quite a lot of games with better combat than Sleeping Dogs.