Founded on Reddit:
"I personally love MMF2 but unfortunately ran into heavy performance snags whenever I exported to Android. Things that just simply shouldn't happen like having more than 10 objects move at one time causing frame stutter. I was spending more time debugging and working around its limitations than producing so I had to switch. Still I highly recommend it for prototyping and or PC development."
"Thanks! One or two of Construct creators used to be pretty involved with MMF2, and I guess they had enough of the limitations and bugs and did something about it. They're both very similar in terms of event scripting though, and both have their ups and downs."
"That would be Ashley Cullen, or Tigerworks as he was known back then. He had an RTS game made in MMF2 (Terminal Orbit) in the works for a few years, but it was never released. I remember he started developing plugins to help in the creation of it, which I guess is what led him to start Construct."
http://www.create-games.com/project.asp?id=89