Hi Slavsky.
I can’t comment too much on Shenzhen – but for Kunming..
Positives:
Amazing weather – think California but never too hot – it has so much sun and I never got bored of that.
Air Quality – Sometimes not great but much better than Chengdu
Travel Options – Nice travel options all around and easy gateway city to Burma, Laos and Vietnam.
Food – Underrated in my opinion, really great food, great BBQ and really cheap and plentiful fruit and veg.
Cultural Diversity – Ethnic minorities-a-plenty and fascinating villages and towns in all parts of the province
Negatives:-
Jobs and Economy – Less developed than Chengdu and I certainly found getting work outside of English teaching easier here, also less options for Western food, shopping etc,
Public Transportation and Taxi’s – Kunming is often at a standstill and the infrastructure projects make ones in Chengdu look carefully planned and well organised.
I believe Shenzhen is great for Business and is a very young city but don’t expect the culture you find in Chengdu or Kunming, I also don’t think the food is that great. You do have HK on your doorstep and it is certainly a better place for work I would say.