"Where there is perhaps a province in which the photograph can tell us nothing more than what we see with our own eyes, there is another in which it proves to us how little our eyes permit us to see." ~Dorothea Lange
That's a great shot! But I don't understand why you decided on such an intrusive border and to darken the surrounding image. I would consider experimenting with a more subtle border.
The photos is fine. I agree the border is too big. it is better with the border but make it smaller. I would also try cropping the photo to enhance the effects of the multiple vertical clouds and the rainbow.