ACE is the new brainchild of Nick Milo - and it is promising
I am not sure that I fully agree with your take on Effort states. My take is that it is more like:
* On - Equivalent to GTD's 'Next Actions'
* Ongoing - Equivalent to PPV's Pillar Support or GTD's 20,000ft Horizon i.e. no end date
* Simmering - Backlog
* Sleeping - Someday Maybe