Question: Why is Unity an easier game engine for me to use than the others?

So I’ve used BYOND’s (byond.com) Dream Maker(DM) engine and SmileBASIC engine for the 3DS and yet I occasionally ran into problems that hours and hours of work and thinking couldn’t solve. It was so difficult. I was really frustrated, to the point of paralysis. On Unity I don’t recall ever running into that much trouble. Maybe I did but I don’t recall. It didn’t leave such a mark. I have solved my bugs/errors/difficulties with trying things out by myself, having someone help me(and they did minimum to me) or google search(google really helps). What are the factors involved in this? I know DM was made by just 2 people Dan and Tom calling themselve’s DANTOM. But Unity was made by hundreds of people. So maybe it’s just more efficient? What about SMILEBoom’s SMILEBasic system? Why is that? What else?