I will use Game Maker:Studio (1.4) because it has all of the features that I want for example:
-Cross-platform building (Focusing on windows nor HTML5 but try to be put on android if the game mechanics will allow it.. :D )
-full featured 2D game framework
- and..I just bought it a couple weeks ago on Humble-bundle so for me, it will be fully legal develop with this great engine :D