I now have everything that worked in IRIS working in Hubitat except my Nest thermostat. There appears to be a solution using IFTTT but I have not tried it yet mainly because I'm trying to keep everything local and I believe IFTTT requires the internet but I could be wrong. My Arlo cameras never worked with IRIS but again IFTTT appears to offer a solution to make them work with Hubitat. To the best of my knowledge everything I've set up has been working continuously with no down time. I read horror stories with other systems that kept dropping devices. But Hubitat just works which is what it should do.
My primary concern was security and now that I have that working my wife is happy and therefore we are both quite happy with Hubitat. I view the home automation part to be a convenience rather than a necessity but it is fun to play with as time permits and I have plans for some additional automation. I am quite happy with my decision to go with Hubitat.