Yesterday, Uber co-founder Garrett Camp wrote "Uber has become a global service providing roughly 15 million rides per day across 500 cities" at https://medium.com/@gc/ubers-path-forward-b59ec9bd4ef6
The most recent estimate I could find on Didi Chuxing is 20 million rides per day as of October, 2016 as stated at https://www.techinasia.com/china-didi-chuxing-20-million-dai...
It's reasonable to assume that Didi has noticeably grown since October 2016, but none of these numbers are easily verifiable externally to these companies.
(Lyft's market share is unclear to me, but perhaps 2 million rides per day, more or less?)
It was apparent that Didi had achieved the network effects necessary to overcome Uber in volume. Both companies wanted to focus on revenue so it was savvy of Didi to purchase UberChina so they could reduce ride subsidies.
I think that the success of UberChina, along with Yum! and Wal-Mart, demonstrate that it is possible to prevail in the difficult Chinese market.
What were the differences?
It was used as an example to illustrate that Didi did the little things that remove friction for its customers. Didi also recruited drivers in smaller cities; its coverage was superior to UberChina's.
It seems to me that to be successful in certain countries requires skills that don't translate internationally - for example, understanding the quirks of one big country, or negotiating the political situation.