I also own a 2011 5.0 and previously owned a 335xi.
I say go with the Mustang, it has a lot more character, and it's a lot more fun (read: affordable) to mod than any N54/N55 engined beast. The 'stang doesn't handle like the BMW (stock, at least), nor is the interior as high quality, but in every other respect I prefer the 5.0.
Also, get it in my color, grabber blue...the women love love love it.
I say go with the Mustang, it has a lot more character, and it's a lot more fun (read: affordable) to mod than any N54/N55 engined beast. The 'stang doesn't handle like the BMW (stock, at least), nor is the interior as high quality, but in every other respect I prefer the 5.0.
Also, get it in my color, grabber blue...the women love love love it.