I've have two Hubitats at two different locations and now have completely disconnected my two ST hubs. This is a description at how I've fared in getting the Hubitat at my cabin to work with all of my devices there. Getting everything to work at my primary home is still ongoing.
The good news it that I was able to move most of the devices at the cabin over and create workarounds for the others. This location always has had an unreliable and slow Internet connection. On Hubitat it is now working locally way better than it every worked with ST. As soon as there is an Android App that allows me to remotely monitor and control it, I'll be very happy,
Devices that were easily recognized and worked well enough with the built in device types.
GE Zwave Plus Paddle Dimmer and Paddle Switches - These paired easily and were recognized. The one challenge was that I wasn't able to get the LED light on the dimmers to operate as I wanted (on when switch is on). Changing the LED behavior on the switches was no problem. I started using the "stephack : GE Zwave Plus Dimmer Switch" driver and was able to change it just fine. How do you access the "double tap" behavior with this device driver within Rule Machine?
Aeotec Smart Dimmer 6 and Smart Switch 6 - These paired easily. I forget if they were recognized but it all works. These are metering devices so it would be nice if that were supported.
Enerwave Z-Wave Smart Relay Switch Module - This paired easily, I forget if it was recognized, but it does work just fine with the generic driver.
ZooZ Zen20 Smart Strip - These paired easily but were not recognized. The Aeon Smart Strip driver does control 4 out of the 5 outlets on these which is good enough for my purposes at the moment.
Devices that appeared to work well but didn't quite.
Zen Thermostat - This paired and was recognized easily, however when I set up a rule to set the mode to "heating", it always changed the mode to "auto". I copied over the Zen DTH from ST without change and it worked fine.
Devices that worked with community ported device handlers. Thanks everyone; this community is great.
EcoNet Controls EBV105-UMK Z-Wave Water Valve worked with "smartthings : Z-Wave Water Valve"
Inovelli Dual Z-Wave Plug w/Built-In Repeater | Control worked with "erocm123 : Inovelli 2-Channel Outdoor Smart Plug NZW97"
Dome Motion Detector DMMS1 worked with "krlaframboise : Dome Motion Sensor"
Devices that worked with me porting ST DTH code over and simply changing physicalgraph to hubitat
Aeotec Heavy Duty Smart Switch, Z-Wave Plus ZW078-A - worked with a port of the ST DTH "smartthings : Aeon Secure Smart Energy Switch UK"
Aeotec Dry Contact Sensor Gen5 , ZW097-A - It took me a while to find the correct ST DTH code for this, but it is "smartthings : Z-Wave Plus Door/Window Sensor"
Aeotec Recessed Door Sensor Gen5 , ZW089-A - worked with "smartthings : Z-Wave Door/Window Sensor"
Devices that I really need, but I can't find any code
Halo and Halo+ Smoke and Carbon monoxide alarms - These have some nice sensors on them and are supported in ST. I currently have them connected via WiFi
Nice to haves
Netatmo Weather Station including wind, rain, and an additional indoor module - These have some nice sensors.