Why Hubitat? Because this community has been moving quicker, provides the widest breadth of device support, responses to issues, and demonstrates that you don't need a big "cloud" backing services to make automation work keeping your home out of the hands of the big players.
Let me just say I was skeptical coming from X-10 Stargate in the mid 90's to SmartThings just over two years ago. It was all due to my HA system being dated and not able to leverage new devices and interfaces. After a 6 month conversion from X-10 to SmartThings and WebCoRE (because SmartThings built in automations were very light on features) I found writing code and leveraging community developed device managers a joy to behold.
Then disaster stuck 30 days of retiring my Stargate, I was on a business trip and the wife called saying that none of the lights were turning off and on, some lights were stuck, sprinklers weren't running, etc. First I thought it was the internet but no, the light on the front of the SmartThings hub was normal, the mobile app couldn't connect, hub was offline in their developer portal. I had to have her work around all the automation until I got home. Then I found out via a one week email exchange with SmartThings that my hub had "self reset".
I had no intention of having to re-register all my devices, automations, dashboards, etc. based on what SmartThings told me on a phone call. After complaining to their U.S. support and dropping a few names they did let me participate in a beta test of having my old hub's configurations and registrations transfer to the new hub.. We spent 3 hours doing this process on the phone on a Saturday after the new hub showed up. With this experience still sour in my mind I started looking for alternatives and Hubitat was on my short list.
I ordered one during one of their sales in 2018 and decided to play around with it. I found it rough, rule machine was in its infancy and tools like WebCoRE were still being ported and unstable. So every 30 day I would update the software on it and try sample automations. The platform progressed rapidly with device support and types of applications. Rule Machine went to version 3 and still had a lot of things that didn't work right for me and it was hard to comprehend when coming over from WebCoRE. At the same time SmartThings started to show that their strategy of cloud services first started to fail, devices status updates got delayed, random device offline, battery power devices draining their battery, etc. I finally had it with SmartThings,
Then a miracle occurred, Rule Machine 4.0 came out on Hubitat! Finally a execution environment that will provide the power of WebCoRE without needing the cloud for backing services. Along with a more "logical" structure of conditions, events, and actions. The Dashboards were also now on par with Action Tiles, and all my existing devices either had native support or the vendors provided device handlers for their switches and sensors.
So 30 days ago I brought on my first automation for wife acceptance, the basement lights, that soaked in for 7 days, then I strategized to move things over "room by room". As of last night 99% of my house is now on Hubitat and running happily. I have about 100 devices, 50+ Rule Machine Rules, 30+ scenes, and the safety monitor all humming way happily. Response times have never been better, wife is happy, I can backup my configuration's and the only internet needed is for an Ecobee thermostat.