Quoted from LovelyCoCoNuts:Wish someone would do something more with opp and mpf
OPP totally works with MPF. Afaik there aren't any open issues. Everything works smoothly software-wise. It is electronically a bit challenging. You need to know what you are doing or you might fry the CPU straightaway. Some projects using OPP are listed here: http://missionpinball.org/hardware_platform/opp.html. But there are more projects around. Most are just not publicly documented. You are welcome to start another one with solid documentation!