The first is best.
I agree that the background mountains don't quite fit in. They look a bit more fractal like in form. In my opinion they should be distant and not high so the tower appears even more surreal large in scale. The atmosphere perfectly supports this scale. Maybe even another tower or two in the background.
I like the greenish water. It is a slightly warm green and gives a bit of colour and depth.
The foreground in the first image has higher contrasts which brings it forward increasing the sense of distance. It also has more and better white snow like textures.
Apart from these reasonably minor issues, I love this scene. The surreal tower like form is fantastic.
