from what I remember while playing with the 7-14, the 11-14 is sharper. The details are clearly distinct. Think Uncle Tomcat would be able to tell us more. Think he have both the 7-14 and 11-22.
11-14 ? ?
Well, the 7-14mm is a Pro-Grade lens while the 11-22 is a High-Grade lens so one would expect the 7-14mm to be as sharp if not sharper than the 11-22mm. I personally did not find the 11-22 to be any sharper than the 7-14mm in their common focal range but then I have the luxury of not caring since they are both well above average in optical quality and ... like Blu said, I have them both.
Which lens I would use depends only on whether the scene needed to be captured with the 7-14mm or the 11-22mm and whether or not I needed to use a polariser. In the 11-14mm common focal range, the 11-22mm would be my preferred choice if I needed to use a polariser especially if water is involved (the 7-14mm seems to do very well with blue skies and surprisingly does not need a polariser to bring out the blueness of the sky).
If the focal range is between 14-22mm, I would prefer to use the Leica 14-50mm kit lens which I find to be super sharp.
The 7-14mm does not suffer from any noticeable rectilinear distortions and is the only ultra-wide digital zoom lens available that is so. Perspective distortions are aplenty and increases as the focal length decreases... but this is to be expected with all ultra wides. The 11-22mm has obvious perspective distortions too at the 11mm end.
Just for curiosity sake, here's a couple of shots taken at the same spot with the 7-14mm at 7mm and 11mm so that you get an idea of the difference in the max. wide angle coverage between the 7-14mm and 11-22mm lenses.
#1 7mm
#2 11mm
And these 2 were between 7mm and 14mm between the 7-14mm and the Leica 14-50mm...
#3 7mm
#4 14mm (Leica 14-50mm)
There was a polariser on the Leica lens by the way.... compare the blueness of the sky in the 2 shots.