That is a beautiful shot, I love the colors. I also do quite a bit of low-light photography and appreciate how hard it is to get as gorgeous shots as what you posted!
I agree with Joergen on the highlights. Long exposures are very difficult to get right with just one exposure. I have had very good experience with some extreme bracketing (eg. 0.5 secs, 10 secs, 30 secs), and combining the results later with TuFuse. (I have a current example on my site under Panoramas, and another one coming soon.)
The key is to get at least two exposures: one exposed for the harsh highlights, another one for general exposure. I generally try to add another bracket, overexposed by four stops to get noise-free shadows. Guillermo Luijk has an excellent article (and a program) he posted on this forum and below:http://www.guillermoluijk.com/article/nonoise/index_en.htm
Yes, this is a lot of work when shooting and in post, but the results speak for themselves!