MMF2 , in my experiences, is easier to manipulate at the lower stages in your knowledge of it.(ie beginner and intermediate). If you really want to take it to the next level then you have to do what most advanced MMF2 users do and download the C++ extension for it.
The other cool thing about MMF2 is all the extensions you can get.
~ mode7 , ~online multiplayer are some of the cooler ones(I can't recall all friggin 50 of them at the moment.
Things like alpha channels, transparencies, etc are all changed via the poperties of the objects as well. You don't have to code them.
MMF2 just is great for beginners that want good eye-candy in like 3 minutes if they have never programmed before.
However, Gamemaker is the better choice since it has GML and is easier to code with.
It also has the better manual as well. MMF2's manual is like("Your First Game") breakout. With the most basic functions...lol and that's all.