I don't find one to be more versatile than the other. The brief is easier to carry because it lays flat against the body. I don't have to arrange my stuff inside the brief like I do with the city. The brief is a "throw and go" bag. The only negative for some people is the shape of the brief. (I like to compare it to an hourglass figure although it has also been refered to as bell-shaped.)
I own two SGH briefs and every time I think about sending them off to consignment I reconsider. They are very fun bags!
I love the brief! It's larger in outline than the city, yes, but it's actually not that big because it's flatter (has less depth to it). That means it sits more nicely against the body when carried. First and foremost you need to decide whether you need a shoulder strap. Then it's the city for you. But keep in mind that the brief's handles are longer so it's easier to carry it over the shoulder.
I prefer the brief to the city but I know I'm in the minority here. And I'm also quite a lot taller than you so that's something else to consider. Have a look at the modeling thread -- there's loads of pics there of the city and the brief being carried.