This is a good overview. Bronk (Research Fellow for Airpower and Technology in the Military Sciences team at Royal United Services Institute, UK) is good, Rupprecht also. (See show notes for links.)
However, both are looking at open source information and someone fluent in Mandarin with a technical background can do even better.
Just a few notes for now -- I may revisit to add more detailed analysis.
1. J10 and J20 are world class fighters, largely indigenously designed. J16 is best flanker variant in the world today.
2. PLAAF missiles (PL12, PL15, cruise missiles, etc.): some argue that PL12 and PL15 are among the best AAM in the world right now. Note use of AESA seeker in individual missiles while IIRC Russians have not incorporated AESA radar in their fighters yet.
3. WS10 and WS15 engines nearly mature -- WS10 now deployed in single engine J10.
4. Note remarks about S400 sales to PRC and relatively small gap between PRC SAMs / air defense and Russian systems.
5. Individual fighter characteristics are becoming less important compared to missile and sensor technology. For example, the low cost JF-17 (co-developed by PRC and Pakistan) is respectable (roughly comparable to early F-16 capabilities) as a plane, but with its block 3 sensor package and PL-12/15 missiles is competitive with much more expensive generation 4+ fighters. The fighter (eventually, drone or UCAV) becomes just a sensor and missile platform...
6. Slightly off-topic: I think the window for utility of stealth is closing fast as radar technology improves. Ubiquitous drones (which can, for example, image stealth opponents from above or behind) and sensor fusion mean that stealth missions over enemy territory against a peer opponent with good SAMs/air defense looks very risky.
The two very obvious and critical technology gaps between PRC and the West were jet engines and semiconductors. It looks like both are on a clear trajectory to close in the next ~5y or so. My guess is that PRC military radar (EM hardware and hardware/software for post-processing), missile technology, and AI/ML are already on par with the US. Sensors, Missiles/Drones, and AI/ML will be the most important technologies for warfare in the coming decades.  
With effectively no technology gap between US and PRC the military equation tilts in their favor over coming decades. Once a country has developed the full stack of military technology their costs are better estimated in PPP rather than exchange rate units: local costs such as compensation for engineers, factory workers, etc. predominate. Since the PRC economy is already significantly larger than the US economy in PPP terms, and growing faster, they can afford more (new, advanced) military hardware than we can in the coming decades. Add to this that their focus is concentrated in the Asia-Pacific region, while the US spreads its capability over the entire world, and it seems almost inevitable (barring economic collapse) that the military balance of power in the Asia region will shift in favor of PRC.