You can buy a Home Assistant hub which is a raspberry that comes with Home Assistant on it. It's designed to be mostly plug and play, but isn't near the simplicity of SmartThings yet.
Once it's setup, a lot of devices can be just added and go. I've got my LG TV added and can turn it on, off, change inputs, etc. I have way more powerful automations and more devices on HA than I ever could on SmartThings.
Depends on your comfort level and interest level