Well, everyone has their own opinions.
Eh. XD I don't know. Personally when the anime started, I really liked Gokudera because he looked tough. But as time went on, I started to believe that Gokudera was mostly bark and hardly bite, and I started to like Yamamoto more.
But Gokudera is cool, personality wise. I remember in the manga, Yamamoto tried to kill himself so early on in the series. I was like, what the hell?