Wow, I like the color and the mood. And the landscape is awesome, it a bit intimidating too, it's sooo big, but I think you did a nice job with it. I think you did a good job in PS with it, not really all that over done, although a little grainy in the clouds, it's okay but could use some NR.
It's a strange crop, maybe a pano or you cropped into the original. I'm a little disturbed by the shot angle and the crop, and the lack of subject focus, not image focus, but there's no main subject (maybe its that all the strong elements in the shot are competing with one another - this happens to me all the time with big vistas and remarkable landscapes). It looks like it's a landscape shot with several very nice elements together (the mesa, the small cumulus clouds, the storm cloud in the upper left, the two rainbows, and the vast expanse) but something is missing, either it's too loose and I'm falling off the edges or it's the "wrong" angle, or the "wrong" crop, or something I cant place my finger on it, but it does not allow me to fee free and comfortable, which is what I think youre trying to achieve given the rainbows and the lighting.
I look at the shot, I see the mesa, then the clouds in the upper left, then the rainbow, then the clouds in the upper right, them after that, I'm feeling a little cut off at the knees, and left wondering around feeling a little lost in the shot.
I know that sounds critical, but I'm trying to describe for you how it makes me feel.
Overall its a very nice capture.
Overall it's a wall hanger, if it were mine, I'd try a little stronger crop, particularly on the left side. Or, I may put back some of the foreground, if there is any in the original. I like it, but it needs to be tighter. . . and I think a tighter crop might help.
That said, you may lose the appeal or the feeling that you wanted by cropping it a bit more. Try it and see. . .