Righto I'll be the guy who jumps in and says "what about brass availability"?
Is the Express easy to find brass for? I imagine as far as big bores go .458 WM and Lott brass is everywhere.
Still, express is fairly different for the usual. (well, I don't hear or read much about it so will say it's less common.) So go for it! Well, go for whatever you want, such is the beauty of firearms.