well i guess i'm in the minority here, but i my Rosewood. I was choosing between the same two in amarante and chose the Rosewood. I wasn't too fond of the snaps on the Roxbury, and the Rosewood holds more than the Rox IMO. Plus, I realized I just liked the shape a lot. And that little pocket on the outside is useful ( i put my cell phone in it, so v. easy & quick access).
I have the Rosewood in Amarante and the Rox in Pomme. Sweetneets's assessment is pretty accurate. The Rosewood holds a little more and the zipper stays closed whereas the Rox's snaps sometimes opens or has a hard time staying closed if you stuff your bag. I also love the outside pocket on the Rosewood--I put my cell in there. All that being said I think the ROx is more sexy and sassy and the Rosewood more elegant. You can't go wrong with either bag.