I really like them and they are probably the best struts you can get for the Mustang. I came from a 2" drop and stock struts with a blown strut and the ride was awful, back breaking, constantly hitting the ground. Since the HD's the ride is so much better, and the harsh, uncomfortable, back breaking, ride is gone. It's still firm but so much more comfortable.
My friend has a Lexus F Sport and he says my Mustang is very similar in ride and comfort.
If you have the money I would absolutely recommend the Bilstein HD's over any other strut.