I'm more of a black person, but it really depends on your own preference. For me, brown isn't as versatile, but it might work for you. Regardless of which color, it's a beautiful bag.
I think I marginally prefer the brown, too, but I think that's because the black leather looks a bit on the faded side in the pic and the goldtone they have used is too light (they appear to have used a darker, warmer, goldtone on the brown bag).
Black and gold is normally a really great combo, IMO, but it has to be opulent looking to work and for that to be the case, the black really needs to be fairly intense (faded and/or greyish black looks better with silvertone HW, IMO) and the gold needs to be rich and warm.
Wow, tough choice. I'd say both but if you can only pick one, my vote is for black. JC bags are very edgy so one has to rock a JC bag in all its glory. Black and gold h/w make a fab combo IMHO. Very edgy, chic, and a complete "wearing-my-sunglasses-indoors-because-i'm-too-cool-for-school" look. LOL