After a long 5 month wait, I just received my Alpa 23mm HR and it's by far the best lens I have ever used in the field. In comparison with the Schneider 24mm XL Digitar, the 23HR has a huge amount of shift capability, and it is also sharp wide open (f/5.6 is like f/11 on a 24XL). I've used the 28HR, 24XL, 35XL, and 47XL and I found that the Schneiders are great to have if you need a large amount of shift, not to mention that the image circles on the XL lenses are quite smooth compared to the HR's. There is distortion at the edge of the image circle for the HR's, but the 23 and 28mm HR lenses are wide enough that I haven't found a need to surpass 11mm of shift. The 23HR is pricey, but the image quality and having the ability to stitch a very wide shot makes a world of a difference for my architectural and personal fine art work.