Mentioned this a bit in the general chat but wanted to post it here as well:
I’d like to get started with it!
What things have people done with it?
I’d like to get IKEA bulbs working with it and @thinkl33t says there’s the option of buying the hub or using USB zigbee things, so that’s something I’m going to look at.
Sounds pretty cool!
Do you mean what have people done with home assistants in general or with that particular platform?
Hi, I’m not a member but saw this post whilst casually browsing (I was actually looking for sewing groups for my partner)…
Anyway I had to make an account as I’ve been heavily into this over the past year. If I was starting now I’d probably go with the ikea bulbs too (I bought a load of hue bulbs + hub a couple of years ago… broke the bank a little bit).
Zigbee in general also looks promising for various sensors you probably want in a smart home (mostly motion sensors and switches I think)… However to do this, like you say, you probably want a vendor agnostic zigbee usb. Theres a few options, but at the moment I think the best solution seems to be deconz with a conbee usb stick, although I’ve not got round to testing this yet.
I’ve been making my own sensors (https://www.mysensors.org)… but I’ve been getting frustrated with the battery powered sensors I’ve been making not working properly… (so hoping to get deconz working with some cheap ikea motion sensors)
Got my whole downstairs set up for motion activated lights, with optional switches too… Automated light and automation settings depending on the time of day (eg dimmer yellow light in the late evening ect)… and cool automatic lighting effects. Getting alexa to activate cinema mode is fun too.
Next I’m interested in implementing facial recognition for people specific events (eg maybe my partner likes certain colours… so they’re activated when she’s home or something)… And then maybe event recognition via machine learning (the house is like 'oh look you’re cooking… I’ll do x.)… not sure how useful that is but it seems fun.
Not tried the other smart home options. I see domoticz and openhab mentioned a fair bit, but the developers for home assistant seem very active and the ui is nice… and its written in python which is the only language I know.
Ultimately I’ve invested many many hours into avoiding using light switches 
Worth it.
One last thing… if you’re setting this up using a raspberrypi (mine is like this)… make sure you have a decent sd card. I had a lot of frustration early on with ha crashing every week or so because my sd card was cheap… and I’d corrupted it by not shutting the pi down too many times.