Huitong has a post on the Z-20 helicopter said to replace the Mi-17:
Mi-17 is considerably larger than S-70 so this comparison of them seem somewhat odd. I would think that both might be used as Mi-17 was said to go in production in China ( How is that getting on? ).A new "general helicopter" in 10t class has been under development at 602/Changhe since late 90s. It appears to be based on American S-70C currently still in service with PLA. However the project was delayed by the development of high priority Z10 attack helicopter. Similar to Z-10, the helicopter also suffered several setbacks due to certain technical/political obstacles, such as obtaining a suitable engine (initially Canadian PT6C-76C, later WZ-9?) as well as developing a new transmission system (with Eurocopter assistance). The project (now designated as Z-20) finally gained full speed after Z-10 was put into production in 2010. The first prototype was rumored to have rolled down the assembly line in December 2012. First flight is expected in 2013. Z-20 is expected to replace eventually the large number of Russian Mi-17 series in service with the Army Aviation.