I also think that Yahtzee is the only game reviewer who hasn't developed a case of the terminal illness 'Fanboysies'. I like how he notices all the little flaws which, to some people, are unimportant - he and I seem to share the same 'every single level in this game looks like a big turd' thought whenever a game overuses the colour brown.
He also talks fast, which I like. I hate it when people talk slowly and so the fact that he spits out his words like he can't stand them is great because it's not boring. Or slow.
I like the visual element as well, makes me laugh. That's as simple as it is, it's just really amusing to me.
All things considered though, he didn't change my opinion on Sonic Unleashed (because I am, quite shamelessly, a fangirl) and I'll still buy Fable II when it's gone a little cheaper regardless of the fact that he said it was crap.
I just find his reviews really funny, to be honest.