No, this isn't the first time we've asked this question.
Reasons to Like the Diamondbacks: They've outscored their opponents by 22 runs (this usually isn't a positive marker, but it's positive in this case because the Giants have been outscored by 13 runs). The Diamondbacks have recently fortified their lineup with the additions of rookie first baseman Paul Goldschmidt and veteran starting pitcher Jason Marquis.
Reasons to Like the Giants: Just a year ago, they won a bunch of games, including four World Series games. They have the same pitching rotation that was so brilliant last year, except they've upgraded with Ryan Vogelsong replacing Barry Zito. They've just added Carlos Beltran -- arguably the best hitter on the market last month -- to their lineup.
Reasons to Dislike the Diamondbacks: Ryan Roberts has been over his head, and their hitters generally have scored more runs than their other basic numbers would predict. Marquis has been terrible. There's still a decent chance that Joe Saunders will turn into a pumpkin well before midnight on Halloween. These guys have never played anything like this well before.
Reasons to Dislike the Giants: Carlos Beltran's wrist is hurting, and the Giants might have traded one of their best prospects for a shell of the Beltran we saw earlier this season. Maybe they used up their share of good luck last October. Bruce Bochy hates Brandon Belt. Orlando Cabrera hates walks. Everybody hates Barry Zito.
Go back and re-read this hard-hitting analysis, just to be sure you've got it all. Then vote, please. The fate of a time zone rests on your judgment.