Still some minor bugs, but overall Eon is stable and for me quite useful. The developer has been very responsive to fixing reported bugs and accepting suggestions for enhancements, so expect Eon to continue to improve. It's completely usable in it's current version, though.
While Eon won't fit everyone's workflow, it's very handy if what you want/need is to see your schedule and to-do list at a glance, without having to open an application, pull down a menu, or go to Dashboard. It's by no means the only schedule viewer available and depending on your needs and preferences another solution might suit you better, but if schedule-at-a-glance is of interest to you, this application is well worth checking out.