Shaderprogramming with gamestudio is just a lot of fun actually
And no, Toast, I of course see the benefits of not having to always reinvent the wheel, I just wanted to mention that at least I sometimes love to reinvent the wheel. But as I also want to finish some projects, I of course also enjoy using other Tools, like for example Unity (I am currently getting into it a bit deeper due to some project). I also worked with ShiVa, even though I can´t really say that I would prefer it over gamestudio. And to reinvent the wheel on a none shader basis, I of course wrote a 2D iPhone engine with OpenGL ES and a 3D Linux/Windows Engine using OpenGL including an awsome shadersystem (just like the one of Gamestudio, but better of course :P).
But I am sure that I am not the only one here for whom the way often already is the goal. But if you are more an artist than a programmer, you of course want a game engine which makes it as easy as possible to create your game idea including fancy effect without having to care on how it actually works.
But well, I am just repeating myself. Unity is awsome for what it is, no question.