Didi is pretty popular, you can get it in most cities, though it really depends on how the regulations are being enforced at the time (didi in Beijing and SH can go away for a few days when there are crackdowns on black cabs). As for rates, check out:

https://ride.guru/estimate/Zhongguancun,%20Haidian,%20Beijin...

That is my standard trip from work to home when I lived in BJ. Didi was just 1.3X more than a taxi, though I usually just took a taxi because wepay wasn't friendly to foreigners at the time.