In addition to introducing a whole new ILC, Fujifilm has also released updated firmware for the X-Pro1. You can grab the firmware from the Fujifilm support site, and here's a list of what it's meant to fix:
1. Improved performance of auto focus*
Focussing in challenging lighting conditions, where light is low or bright, will now be much faster in Auto Focus mode. The focusing distance has also been improved, allowing you to get closer to the subject and capture a great shot without switching to macro mode.
2. Manual Focus improved performance
(1). Improved operability The speed of the image coming into focus when turning the focus ring has been vastly improved. When adjusting the focus ring using the electronic viewfinder or the LCD panel on the back of the camera it is now much easier to focus, always displaying the image closer to full aperture with minimum depth of field.
(2). New addition of 3x magnification for checking focus The 10x magnifications / focus check feature on the X-Pro1 has been well received and in this firmware update an additional 3 x option is now available. It is also now possible to find the optimum focus point whilst viewing the entire screen.
3. Improved writing speed/ processing speed.
(1). Improved writhing speed to memory card At maximum speed the X-Pro1 can now write to memory card twice as fast as before. **
(2). Improved speed for playback after shooting Image playback now occurs less than one second after pressing the image playback button. On some occasions previously, for example when using continuous shooting, you had to wait until the images had been processed before it was shown on screen.
4. Other additional functions
(1). New addition of "Auto (6400)" to the ISO setting
DPReview has put together a hand's-on with the new firmware, and it appears to significantly improve the user experience. Apparently write times have been massively improved; you can now playback while writing to SD card; and both auto and manual focuses have been noticeably upgraded, especially manual focusing thanks to the lens aperture now staying wide open.
This should hopefully fix a lot of the problems that X-Pro1 users have struggled with, making it that much more of a competitive camera.