I selected both, only because there is no option that says:
"Yahtzee sees video games almost precisely as I do, and therefore, prevents me from wasting money on games he knows I won't like."
A good example of this was Devil May Cry 4. I absolutely loved DMC1 and DMC3. When I watched his review I knew right away that, even though DMC4 may have some good hack'n'slash aspects, I would regret committing $60 to it.
I tried DMC4 at a friends house a few weeks later, and found Yahtzees words rang true.
Also, Yahtzee saved me from the embarrassment of purchasing Mirror's Edge: One of my best friends was saying it was going to be a great game.
Later on, I tried that game at my friends house and found it to be craptastic.
In short, I trust the reviews that Yahtzee provides more than any magazine -- because I can actually relate to his preferences in gaming.