The Verge did a nice post-CES write up on the state of Home Kit. In principle, it sounds pretty appealing to me as an Apple device user. It also sounds like it isn't completely ready yet either. I've been a little surprised at how slow Home Kit has been to roll out. It was announced at WWDC and you still can't buy Home Kit enabled devices. I suspect this has to do with dialing in the API's and making deals with the hardware manufacturers. As soon as Apple announced Home Kit, I stopped buying third party automation devices. I'd like to see how this plays out before investing any more.
In some ways, the home automation racket feels a lot to me like early computers where there was no clear winner and it seemed like everyone wanted to get into the game. Right now, I don't think anyone has an idea where this is all heading.
My guess is that ultimately Home Kit devices will include a slight premium but will be much easier to use from an iOS device than their competitors. You'll even be able to use Siri to control your devices. (However, according to the Verge, to use Siri from offsite, you'll also need an AppleTV.) My inner twelve-year-old would love talking to my Apple Watch at the Airport and turning off lights at my home.