I look forward to playing it as they roll out more material. But my immediate take-away is that it is basically a really interesting framework and won't feel (to me anyway) complete until the equivalent of the advanced race and player guides come out.
Right now, it seems a little thin. Not a lot thin, just not quite enough customization options to get my players to want to run it at present, aside from some short forays into the new rules. In the end, if we didn't like the customization options of PF, we'd play 5E. Even core rules aren't 5E but they are far less than mature 1E :)
So, we're starting another PF 1E campaign and will see how it looks when that ends. Of course, I've been devouring the rule book and plan to do a few trial one-shots. If my players are happy enough with what's there now, we may end or convert the earlier game and go to 2E. We'll see.