I was just at a workshop for GMStudio. Since a lot of the people in my community are new to game development, the GGJ event organizers thought it would be nice to teach some basics to get them going. Stencyl is still 10x easier than GameMaker to jump into. However, I was quite impressed at the compile times. I produced an .exe in less than 1 minute (more like 15 seconds). I'm sure it takes longer as your game becomes bigger, but still...
It is nice to have other options open because you can't always find a group that uses your toolsets at Global Game Jam. Now at least, I would consider joining a GM group.