Seems to me that you're going by only HRs. Nixon's OBP is higher and he is a better contact hitter, which I prefer to a guy that hits HRs once every 9 games
Even if he hit a HR once every 5 games and he didn't strike out once every 3 at bats, what do you have to say about his fielding? He's got a good arm, that's for sure. But I can't say much else