Everything i've seen discussed here points to J-20 having the technological and performance edge over the F-35. Probably earlier variants have GaN radars while the A/S might have GaNS radars, when GaN radars won't be fitted to F-35 for at least another 5 years. So yeah more US delusions. Of course that doesn't mean China should slacken it's development efforts, on the contrary, push even harder to stay ahead and widen the gap.
On another note, would it be too much of a push to say that chinese fighter radars at least are as superior today compared to US counterparts as the US radars were superior to their soviet counterparts during the Cold War?