One shortcoming of the ecobee-HomeAssistant integration is the lack of fan control and status reporting. There is no way that I've seen to run the fan manually from HomeAssistant and no status indication if only the fan is running. Probably some way to get around this but I haven't seen the need to dig into it.
I have only the experience with the GoControl GC-TBZ48. I paid $79 for it and thought it was a steal compared to the big name products.
Initially it worked great - I used the available system driver and was able to schedule by mode which really suited my needs. Recently (and I can only surmise why) I started burning and churning through batteries. Long story short, I changed the 3 wire thermostat wire to a 5 wire and was amazed at how well things worked after that! I gained fan control (being able to turn the blower of the furnace on, without the furnace on) which to me is 'circulation' and it is awesome!
So, evolving from that I implemented the Thermostat Control app to create a virtual thermostat that allows me to use remote temperature values from my motion sensors. That took 1/2 a day to dial it in, but I now tie my real thermostat to the controller, and the controller to the scheduler. I also switched from the system driver to @bptworld 's Advanced driver. There sure is a learning curve about a lot of things like deltas, and MOT's but it was a work of love and I'm ultra happy with my setup. As a bonus, I have simple voice control via Alexa as well using the Amazon Echo skill.
You can do ecobee fan notifications with the default integration, but it's cloud based. It will report if fan is set to auto or on.