Can you please update the first post to include links to reviews and info in this thread. Updating the title too (removing the 'pro') would be good too. It will avoid repeating the same questions and answers especially useful as it looks like it won't be at least a month till more reviews come in.
Brand new, the K812 will sell for £1000. The HD800 brand new still sells for £1000. Priced the same guys.