Unity is a full blown engine capable of pushing out indie titles for a wide variety of platforms, from an online web player, to android, to major consoles. Being cross platform is something I enjoy as an alternative to C# and XNA. The Unity engine also streamlines much of the development process with a graphical user interface, so I can focus on the most important thing: Development.
I’ve been learning Unity since late 2014 and I have to say that it is my new best friend. Some day, I hope to maximize my gains by purchasing the pro version, but as it stands, I’d have to hold serious profit margins for that to happen.