I don't know what they've changed in this release version from previous ones. I tested it for some time before release as private beta tester and i can say :
1 - Their GUI is awesome. But can be slow at times
3 - The event blocks system looks good , but requires more clicks than Constructs. The advantage is that it can be more intuitive for novices and event kids (or maybe not), but not necessarily easier.
4 - The overall runtime speed was kinda poor on previous versions, don't know how it is now . I have a feeling HTML5 tends to be faster but i'm not sure.
5 - It uses Box2d to handle everything. This is good sometimes but may become a problem if one wants a customized control over collisions.
5 - On the versions i tested you could define collision geometry as polygons but only by inputting direct values of point coordinates, terrible . I'll check if this has changed.
6 - Parallax was much less intuitive and cumbersome to do than Construct . Again, i'll check this.
7 - Overall : Biggest advantages over construct : Integrated support for Community share over tutorials , assets, games , game hosting etc, publising on major portals etc.
And : Support for editing code directly.
And of course : Their site is very well done.