I am using HG. I bought a first gen RPi and have it set up with Raspian Jesse and HG as a service. In order to do advanced things, you will need to do some kind of scripting, but many of the basic things are straight forward. There was a very healthy user community but the author recently decided that unemployment and no financial support for his side project wasn't working out so he's basically suspended development. The source is open so anyone can make updates and publish them but the code is pretty complex and not exactly suited for entry level programmers to pick up and run with.
That said, you don't really need to know anything about the guts of HG to use it. It's fully functional and has a lot of capabilities. I've written a few scripts in C# that are available. There are a lot of others that have posted their work so you should be able to access/install them directly from the interface. If you want to do something that's not in the built in feature set or a user provided script, you have the opportunity to write it yourself. I think looking at scripting as a negative feature is backwards, personally. I specifically searched out a HA system that was open source (or at least very low cost), compatible with X10 and the CM15A, could run on some type of low power computer (RPi, Android stick, etc), and had a true scripting language. AHP does not have real scripting and the ways to make it work are a kludged work around IMO. I'm impressed by those that have made it work, but that's not my approach.
