Admittedly I have not been looking recently for a different HA software as HG has sat quietly running on my RPi3 without issues for a long time. The SD failed so I dropped a backup in and away we went.
That said, before picking HG I looked at all of the available options that could use X10 and could be run on a SBC. There are other options available that will work with X10 and technically are just as capable, however they are a bit of a hack to make everything work. Last I checked, home assistant could run both PLC and RF X10 however while PLC was natively supported the RF required a wonky work around that I didn’t like. It would work if you needed to use HA. I believe Domoticz would have worked too, but I haven’t checked them in a while. In either case, they utilize mochad to integrate X10 which is robust and works well however is not fully integrated like HG. IMO, HG has the best X10 support and until it stops meeting my needs, I’ll probably continue using it.
If others have a different perspective or more thorough/current knowledge on other fully integrated X10 options I might be swayed to look again. 