The only thing you can find online is usually catering to rich western tourists or "expats" and usually boils down to "Which place is the most western/ High GDP and McDonalds!" so I'd rather get an opinion from someone that's been there that isn't a business tourist.
Shenzhen, modern city. Busy city, good job opportunities should be a thing if you know Chinese sufficiently. Amazing metro, and if you want more capitalism, visiting Xianggang(Hong Kong) is a breeze. I enjoyed my (quite long) time there