I got mine today. First impressions:
It's the same as the old one...
...but it has TouchID, more rounded corners, and a USB-C to Lighning braided cable.
Actually, at a push I'd say it's slightly quieter and better damped than the old one. Not a big jump, not like the recent changes in MacBook keyboards, but it does feel slightly different. Maybe it's because it's new and hasn't been used much, I don't know, but if a change is there it's very subtle.
I bought it for TouchID so I'm happy regardless. I couldn't possibly recommend it as an upgrade to an existing Magic Keyboard user as the differences vs cost don't stack up for most people, but I am content with my purchase because it addresses the only thing I miss from using an external keyboard and a MacBook Air in clamshell mode.