I grabbed one today, with the Immortalizer. Broke the bank but man, is it awful nice.
My only comparison was my K101. It's MUCH nicer in terms of build quality and threading, hits a little more consistent and by the end of my work day, was still hitting like this morning... I don't know, it's a tube mech. A fancy battery holder. Was it worth it? I say yes, but keep in mind your biggest returns will always come from your topper.