kwaigonegin
Colonel
You know what I think ??
I think that the Russians offered the Chinese Su-35S which is the same model Russians are using, however, China thinks that it is garbage. Su-35S is much better than the Su-30MKI but now it is 2013. China has J-15, J-16, J-10B not forget to mention J-20 and J-31.
So basically China told Russia to FU@K off with its Su-35S and told them that Su-35 must come with advanced Chinese avionics, weapon systems. Russia know that the avionics and weapons are what is making them money, therefore the deal can NOT be reached.
China does not want or need the Su-35S, Russia however desperately want to sell it to make money to fund its crappy under funded PAK-FA. Russia knows that 117S engine is the only selling point for the Su-35, but now it is over. The new J-20 2003, and 2004 prototypes showed that it is using AL-31FM1.
Game OVER !!
I would say Russia still has a slight lead in engines but China is catching up fast. Once all the bugs are ironed out and they have the tooling and infrastructure in place to mass produce engines like the Taihang, WS15 etc then it is really game over for Russia. I can see China being a major arms exporter after the mid 2020s and beyond.