So I ran my first D&D Next game yesterday (I recall testing it once a while back when it was in beta stage but only lasted a session I think). Kain was my only victim because the rest of you are jerks.
My favorite part is the simplicity. I have a lot more experience with 3rd Edition, particularly 3.5 and Pathfinder, but if I had the same time with 5e I probably wouldn't even need to reference the books. It was also very convenient to have a bunch of normal to great human type guys in the back for quick use (though I ended up only using one of said statblocks).
The fact that charging isn't a thing (at least by default rules) in this edition really threw me off. Forced me to change the way I ran the first encounter. Probably just as well, as said first encounter might have ended up killing the NPC whose sole purpose (from a metagame view) is to keep Kain's character from dying from some CR 1/8 encounter.
Speaking of which, it is a very good thing these exist, and in quite a variety, because with a lack of healing classes among them it's entirely possible that a single CR 1 monster could kill Kain's character and/or some of his allied NPCs entirely by luck. I get the impression this game expects you to play smarter than other editions, particularly at 1st level. It certainly rewards smarter gameplay to an extent (but hey if your rolls on the surprise arrows both suck there's nothing you can do).
The worst part so far is only having one player.