so, update...
Upon arriving to Beijing, the uber app automatically switched to the china version (same app but different start screen, all in english), my original account did not work, but creating a new one was possible, and thats when the good news ended.
upon registration, payment had 4 options, alipay, baidu pay, international CC and unionpay(iirc).. Unfortunately neither my european Amex, MC or Visa were accepted as international CC and i wasnt able to get ali pay or baidu running....
Thus making Uber unusable for me in Beijing