If I was in the market for a new TV right now I'd be all over the 50" model. I almost bought one anyway.
edit: I'm still considering pulling the trigger anyway. Camel shows this as coming down from $1500 in the last 6 months, and the reviews are solid. I won't even use the 4k feature as I'm still firmly locked in 1080p everything, but for the screen size and other features the price is outstanding.
Who on earth buys a 4K monitor / tv to use it at 720p???