"Weâre now using wireless prototype controllers to conduct live playtests, with everyone from industry professionals to die-hard gamers to casual gamers. It's generating a ton of useful feedback, and it means we'll be able to make the controller a lot better. Of course, it's also keeping us pretty busy making all those improvements. Realistically, we're now looking at a release window of 2015, not 2014.
Obviously...

This is disappointing, but I trust them that it'll make for a better experience in the future. Maybe I'll just build my own :)
I'm becoming more and more a fan of delayed production of technology. Let it simmer, perfect it, and then maybe it will be something worth buying. Rather than just enter the console market, what Valve is attempting is more along the lines of a revolution.
"But our number one priority is making sure that when you do, you'll be getting the best gaming experience possible."
I want that more than I want a Steam Machine, and I really want a Steam Machine.
I'm ok with this. I want that thing to be as close to perfect as possible.
I dont expect this controller to make much of an impact, but I am not really a believer in the steam OS
Fair point. Because it's so different, Valve has a lot of ways to go to make the new controller great. I hope it works out for them but I am thinking I may have to buy a bunch of controllers to make my steam machine work right.
But either way, it should be awesome anyway.