Is that really a point which matters nowadays? Fast hardware is cheap. Throw some 40-50 bucks on HW like this and problem solved? http://www.hardkernel.com/main/products/prdt_info.php
What I can see, OpenHAB has an active thriving community. A tip to use ODROID hw was from there and not many months old.
Eventghost runs on Windows PCs only. Which is quite a limiting and power consuming.