I had the one with the Horus (sp) software, and I have to say, I really didn't like the lack of ease of use. Especially when it first came out... and you could find or get the Horus software.
One of the other issues was that there were updates as they changed the firmware.... that is to say, the Kestrel could not be flashed with newer Horus software.
I'd REALLY like to hear some final thoughts one you guys get some serious 300WM trigger time.
I too am, shall we say, getting older, and I'm not as sharp with remembering everything on the fly.