Looks cool....but pricey. I'll be very interested in your review once you've used it a while. Battery life, key size, ease of pairing, responsiveness, how well the Logitech software works, etc.
I "pre-ordered" from the Logitech website and it shipped the next day. Reviews for the K810 are the exact same for the K811: it's the only wireless, illuminated keyboard with Mac-specific keys. I didn't even install the Logitech software since it works so well out of the box. It feels small if you're used to a keyboard with a number pad but it's exactly the same size as the Apple keyboard (and better looking).
I paired it with my iPad & iPhone just for fun to see how easily it switches. I don't expect to use it on anything but the iMac though.