HA-Bridge is a good example of a multi platform software solution which many run on a Raspberry Pi.
IMO, at minimum, this is geek stuff, at the extreme it's for dedicated coders.
This is where AHP clearly was a cut above the rest. It was relatively easy to create macros and maintain an increasingly complicated system. This is also where HomeSeer took that approach and improved it. The HomeSeer events are substantially more involved than AHP stuff, yet still relatively easy to understand and create.
Everything else I've seen pretty much requires a coding degree and/or is painfully complicated. The java based apps are impossibly slow for me. Obviously, there are a bunch of systems I've never tried so there may be something else out there but I doubt there is something with the simplicity and power of the defunct AHP software or the current HomeSeer software. Certainly, most of these other systems are not at all intuitive and that's the key to having a system that's easy to use and understand.
HomeSeer supports X10 but IMO the only reason they support X10 is to get X10 users to embrace their technology, which is slowly happening. There is a very active X10 base of users on the HomeSeer forum and they're not waiting for some Wi-Fi unit, they've moved on.