Pro does ask for a key, and cannot be installed without one. It also automatically activates if you're connected to the Internet. So much for the old advice of not activating virtual machines.
The RTM also still defaults to "private network", complete with a home group, with my direct Internet connection with public IP address. It's like the least secure configuration possible. And the way to change it to private is no longer available in the Network and Sharing Center, but hidden in the charms bar and confusingly named "turn sharing on or off".
Other than that, it's definitely a lot smoother and more polished than the CP was (never tried the RP). We'll see how it goes.