Wow, that's an interesting description (the "alpha and limited compatibility" part). I've used both Zeus and Spring and I've found Spring to be more reliable. I've run into a number of issues with Zeus where it crapped out on me. I've never hit any such issues with Spring, it's felt very stable. I see the Zeus issue (#254) that plagued me the most has been fixed now though: it can now accept arbitrary-length commands. So maybe it's more usable now.