I don't know about the Ashley Express on a Kimber but I have them on my pocket gun (Kel-Tec P-11 9mm) and they are perfect. They seem to be the fastest sights I have used in terms of picking up a good sight picture. They are designed for up close and personal encounters but not great for those long shots. I would highly recomend them for any carry gun.
I had the Ashley Express Tritium Big Dot sight put on a Kimber Custom Classic a couple of years ago. Kimber had me send them the slide, they installed the sights and shipped it back. The service from Kimber was excellent.
The sights are great for fast target aquisition on up close targets. But on distance and precision shooting, the front sight covers up too much of the target.
For me, the Ashley Express Big Dot is the way to go on a personal defense gun.