An update:

Overall, my HomeKit system is functioning really well. It's super fast (especially in comparison to my ZWave network), and everything - for the most part - just works.

There was a couple days there where I gave my Hue hub a static IP address and that completely screwed up the system for some weird reason, but a couple days and many Apple TV restarts later it finally cleared up.

I've now replaced almost every ZWave device I have. I still have six switches, my front door lock, and an outdoor light switch (for landscape lights) left to replace. I then plan on adding the MyQ hub for my garage doors, and I'm thinking of replacing my Nest thermostat for the Ecobee. The Nest can only work with Homebridge, and at this point it doesn't make much sense to set up Homebridge for one device. Besides, I could probably sell my Nest for almost as much as an Ecobee 3 costs. They don't look as nice and they're not as great to control, but they'll work with HomeKit.

Has anyone else here dabbled in HomeKit?