After having played with an Echo on and off for the last two weeks I'm honostly pretty impressed. The hinge is REALLY well done, doesnt feel week in the least bit. The apps work really well across both screens. The "simul-tasking" apps actually add functionality and work as advertised. And the phone itself is quite snappy and hardly noticed any hang ups at all. Oh and its pretty much stock android which was pretty nice of Kyocera not to crap all over it.
I am hoping to get my hands on one today. I have heard that the hinge mechanism is pretty solid, which was one of my concerns when I first saw it. The fact that it comes with a "spare" battery will help make up for its assumed talk time listed.