Forgot to mention the complete loss of a home screen your way. The CCGTV brings "Google TV" and the new home screen that wants to aggregate your entire viewing experience and give you a ton of recommendations, many of which are for services you don't currently pay for.
Whereas the TS4k still uses the Android TV home screen which has app specific row you can choose. You can also disable Tivo Stream and related apps and have even more control over how you organize the home screen.
And the remote kinda stinks. It's basic and has no real dvr functionality like the TS4k does. As others have mentioned, button mapper is your friend.