Has anyone heard the new dynaudio confidence 20 bookshelf speakers? 

Not much information on these.

How do they sound?

What are the alternatives? 
Facepalm, OP is talking about the new Confidence, not Contour. Confidence is not out yet, they’ve been delayed. No one has heard them at a dealer.
But I've seen the 20's being sold online on a couple of European sites so I am not certain about that.
The new Confidence (20, 30, 50, 60) aren’t yet in production and a single pair of pre-production prototypes for each model are making rounds to shows and special events. I was lucky enough to hear the 60s at my dealer late last year, and they look and sound fantastic, but they will be $40K+.

No doubt the Confidence 20 will be better than the current C1s but they will be more expensive too (~$12K with stands). I believe the new Confidence are due at dealers 2nd quarter of this year.