Ask HN: New York vs San Francisco (Tech Edition)

All, I have lived in San Francisco for a couple of years now working in tech. I am not thinking about potentially moving to NYC. I would appreciate a career discussion of what it means to move to work. I work in data science if that helps narrow things down.

I would also appreciate comments on how the two cities compare. I have read articles about how NYC is always on but SF is more laidback but I am not sure how that fits in tech (which I feel is always on). Also, some thoughts on cost of living in both cities and salaries would be greatly appreciated.

Thanks!