Fujifilm announced an X-Pro1 firmware update along with the X-E1, basically bringing the X-Pro1's firmware up to the same level as the new camera.
The two primary improvements are: focus speed, and card write speed, both of which use new algorithms to improve performance. The focus changes are most dramatic on the 60mm macro lens and in low light, but the write performance improvements are quite evident in pretty much any kind of shooting. Users with reasonably high performance cards should see 50% or better buffer clearing times. Fujifilm claims a 2x improvement with UHS-1 cards. Manual focus also gets some attention, adding a 3x magnification option and fixing the fly-by-wire focus ring performance. Finally, Auto ISO with ISO 6400 max has been added.
The update isn't available right away. Fujifilm says they'll be making it available on September 16th.