I got the hub on Friday and was excited to set it up immediately. It took over an hour to remove the devices from smarthings and add them to hubitat. I then created many of the automations I had working in smartthings using rule machine and all was ok-ish. Response times were definitely faster than with smartthings and being a tinkerer I was happy. But I soon ran into a couple problems that eventually sent me back to smartthings.
Firstly I have a iris keypad that worked great with smartthings. I was happy it was listed as supported by hubitat and seemed to work great except for one thing. When arming and disarming the lights on the iris keypad would stay on unless I triggered its motion sensor then they would go out. It was annoying, especially because I knew my wife wouldn't remember to do it (the batteries drained from 80% to 20% since Friday because of this) but I pressed on with hubitat nonetheless.
The second issue and deal breaker for me was that all my bulbs are sengled classics and with smartthings if someone turned the physical light switch off or on, it would reflect in the smartthings app immediately so my automations would work but with hubitat that was not happening. I have an automation that turns off my kids room lights if there's no motion in the room for 8 minutes. That automation checks 2 conditions - the motion sensor being inactive, and the lights being on. If someone used the physical switch to turn the lights on, hubitat can't tell that the lights are on and thus my automation wouldn't run.
This 2 things plus the lack of a good app with a nice GUI just turned me off so I removed all devices from hubitat this morning and went back to smarthings. Yes some things will happen a bit slower than with hubitat, but I can live with that.