Interesting subject and a great find for this challenge. The colors are what I find really appealing in this shot. Exposure is fairly well handled however the sky is a little dark and as mentioned the masking did strange things to the clouds. I think the composition could be improved perhaps by shooting from more of an oblique. It would also be nice to see water in the shot (if that was possible).
I like the composition and color. I can see that you masked the sky. I find the bright cloud destracting, constantly pulling at my attention. This image would look nice in BW as well.