Another difference I recently read in another thread here is that while RA2 Select works with Lutron's occupancy/vacancy (motion) sensors, it doesn't expose them over telnet. Thus, they are pretty much useless to Hubitat since it can't "see" them, and they are only usable within the Lutron system. This is also mentioned on the Lutron forums and a community-created Home Assistant Lutron integration Github. and "Full" Radio RA2 systems do not have this limitation.
In related news, if anyone wants a Radio Powr Savr occupancy sensor I bought under the mistaken believe I could use with RA2 Select, I have one. 
I'll be sticking with Caseta (and if they ever come out with a motion sensor for Caseta, I hope it can be exposed over telnet, though I'm not sure I'd hold my breath considering it's not true for RA2 Select).
