Not to be left behind by this quantum leap in technology the Russians had the Sukhoi design bureau design a competing product. The T-50 (nicknamed the Kraptor by cynical American officers) made its debut in 2010. Although it looked like a Raptor from a distance it was quickly noted that many of the technologies that the make the F-22 a world beater were absent. To begin with there was no vectored thrust.
In 1964 Red China decided it neede to build a domestic fighter. Based largely on MiG 21 aerodynamics the J-8 was rolled out in 1969. For political reasons production and delivery was delayed until 1980 (chalk one up for yet another cultural revolution). By this time the west had moved on to infinitely more capable platforms such as the F-16 and F-15 Eagle. The J-8 was hopelessly outclassed even by the Russian designs of the decade. In the 1980s the Chinese had managed to deliver unto themselves the best of 1960s technology.
With new 6th generation fighters already being test flown including unmanned ones, it is safe to say that Chinese Medium range Ballistic Missiles are a far bigger threat that the J-20. But then strategic planners have commented that the J-20 may be just a part of the Chinese battle plan. If they use MRBMs to knock out our airbases in the region then they may believe they could rule the area uncontested. F-22's would have to fly long distances and use aerial refueling. But then that is why they have super-cruise (Mach 1+ speed without afterburner) and refueling probes.
The J-20 seems to be yet another example of delivering the very best of 20 year old technology. A few angled corners and a digital "disco dash" cockpit display do not a world beater make. This jet may represent a jump in technology for the PLAAF (People's Liberation Army Air Force) but it still puts them well behind the west. There is no evidence of a Raptor style integrated digital satellite linked "God's eye view" combat system that is linked to all other aircraft in the battlespace (but that does not insure that it does not have one). Stealth experts have already determined that the stealthiness of the plane is not up to western standards. Not only the shape is critical to low observable aircraft but also the materials. Northrop-Grumman and Lockheed-Martin can attest as to how difficult these materials are to master working with. It would appear that the J-20 would have been a great plane in 1980 but it is late to the party; ergo it is the late, great J-20.