It’s a mixed bag. On the one hand, I like the potential it opens up, and I feel it’s on the way to becoming a decent site builder, at least for developers who know what they’re doing.
At the same time though, I have to wonder whether this is going to work for normal users. I mean, does this really make it easier to add content? I’d say no, and that’s even on the type mobile devices the system seems to have been designed for.
It’s also quite buggy, sometimes adding or removing spaces and line breaks at seemingly random. Not a good look for something this important to WordPress.
Because of that, I’d say it’d probably work better if enabled solely on static pages, and that it should probably go through a few more rounds of testing before being integrated into core.