Despite its hype, it doesn't have the design overlap it claims. I only played with the on-line version but noticed the desktop version "imports" from other websites.
If you therefore wanted an adaptive solution you could use Xara to master the design elements and NicePage to generate the variants.

It doesn't have all the clever things Xara offers around pop-up layers and rollover effects. Embedding of code is CSS to the page.

It seems to have a slickness about its web aspects that Xara lacks but Xara is the designer winner.

Blend the two?

Acorn