I like the layers of colors in the sky, and especially the wispy clouds. Though I think the horizon and silhouettes are too minimal. They seem more of a distraction than an enhancing the sky. Could try cloning them away or lighting them up some.
The sky in this photo is amazing. It's great that you could capture it but try when you're editing to bring out the cityscape a bit...the outlines would be outstanding if they were clearer.