Ahh, so you know of blender?? Cool shyt. I've been using blender over 8 years of my life. Blender is all I know. My first love when it came to creating games. It taught me everything I know about programming, animation, modeling and texturing. If for no other reason, I use it out of loyalty. But to answer your edit, I dabbled around (and still) do with a couple game engines. I've messed with Amazon Lumberyard and even made some tutorials about it on my channel. It's the newest engine out, but its based on CryEngine.... Then I messed around with Unreal Engine 4, which has the greatest potential for me to transition over to, and I think I will inevitably migrate to that engine if and when a game of mine becomes successful online. I told myself if my games began making serious money, then yeah, I will likely continue my career in UE4. Until then, i simply don't have the time to learn the ins and outs of the software right now.
CryEngine is buggy and undocumented as hell. Not alot of indepth tutorials about a whole lot of useful stuff, and requires heavy programming. And finally, with Unity 5, my greatest (and only) gripe was that the game has to be entirely programmed manually. I do know how to program, but with Python only, and Unity uses C#. One thing Blender and UE4 has over unity is that they don't require hardcore programming, they have visual scripting built in the design.