Here is my quick test using X-Pro1 + Fujinon XF 14/2.8
Original image, before the correction:
Screenshot, DXO Perspective interface
Final image, after the correction (both horizon and perspective)
Same original photo corrected in Lightroom 5:
I like DXO Perspective. It is very easy to use and final result looks very good, similar (identical?) to the Lightroom output. If you are on OSX and don't have any other perspective control tools (like Lightroom, Photoshop, etc) then you may want to consider it .