Don't spend forever, set a deadline of a few weeks and just compare. UPStart only works with UPB. PowerHome for configuring Insteon is because Smarthome never had anything like UPStart so Powerhome did a better job and made it easier to configure Insteon. UPStart is free, will work with any brand UPB and is downloadable from SAI, HAI or PCS. With Elk you need a dedicated M1XSP because the Insteon firmware is separate. It would be best to just have 2 XSP's hooked up, 1 for Insteon and 1 for UPB and run it side by side. If you only have 1 XSP you will need to reflash the firmware to go back and forth - doable, but not ideal. There are no issues running 2 of them side by side.