I've been playing with it all afternoon, I haven't tried everything yet but now I've got use to how it all works I have to say it is impressive. It looks great on mobile and on all devises I've tried.
The ability to use different elements in your design on a page by page bases is something I've wanted from WP for years. And included in this free version there is a good number of elements oyu can add to your template. The only negatives i've come across so far are:
As far as I can see when you add a section you can't only add it to a given page or say only categories. I used a HTML box to add a featured post section on the top of the home page and it added the box to all pages with a text like "add content". I had to set in global settings some random html like <b></b> plus css 0px 0px in options to get rid of the text on the top of all pages... the negative of this work around is that the box code is still added to the source of the page, so although you don't see anything, it makes the content on the page page drop by a number of pixels, not a biggy, but I lost a lot of hours with it....
You can't edit the template your self and add code... you will always have to use their html boxes to add code for other plugins etc.. which is a little less flexibly than hard coding it (example problem mentioned above), then again it does mean that when you update the theme files there's no need to go back and code it back in.
It will of cause depend on your needs, but so far I think in most cases the positives way out way the negatives, It looks like I'll be using it on most of my projects for the time being.