This question is not about Game Design, so I'm moving it out of the Game Design forum.
so where you are moving it?
Are you a programmer? I'm struggling with that issue myself.
I'm a C# developer and have used C# since it first came out of beta so XNA was my first choice, but developing a game engine from scratch may be a bit more than I want to get involved in, so I am looking at Unity as well so I can focus on game design and less on having to code an entire engine from the ground up.
I think that, like development environments today, that engines like Unity will become more commonplace as they make our design work a lot easier and faster to use.
Thanks for answer, I think UNITY is the solution...