What are the main differences among xiamen, hainan and qingdao? Trying to pick one as residence

I want to live in a warm climate, clean city, good economy in China. These three cities have come up as options. But I have not been to any of them: hainan, XM, qingdao. I would welcome your opinion if how XM compares to the other two as an option for an expat looking for a warm, clean, sustainable place to live in China. I am open to suggestions. Thx!