I think there is a bit of a case of confirmation bias against reliable engines.
We only ever hear stories, or indeed, pay attention when something goes wrong. With engines, especially on single engined figures, that usually means something going catastrophically wrong.
However, there is nothing really to report if an engine is working perfectly, even for years on end.
I take it was a plus that it has been years since we heard any major stories about the WS10A, because as far as engines are concerned, no news is good news.
With over 400 engines operational on hundreds of fighters for years already, if there was still serious issues with the WS10A, there would have been persistent rumours, and the PLAAF would not be integrating it on the single engined J10B/Cs.
People often make the unfounded assumption that China is aiming for the WS10A to match AL31N performance and reliability, when I think China's aims are far more ambitious, and they are in fact using western engines as a benchmark to measure themselves against.
In terms of reliability and durability at least, I would expect the WS10A to be way ahead of the AL31 in terms of design. There were some early hiccups with implementation, but with those resolved, the WS10A should prove to be a superior engine in those regards.
The AL31 may still hold a slender raw performance edge, but that comes because of the design compromises made to maximise performance at the expense of lifespan and reliability.
Russia is in effect overclocking their engines to get better performance, while China is following the western approach to design fundamentally better engines.
Such an approach is much harder and takes longer, but once accomplished, should yield far superior fruits.
