as the moment right now F-22 is the best because it was designed for "first look first kill besides it's already in deployment in replacing the iconic F-15 which had many records it holds like kill ratio, while Sukhoi T-50 and Chengdu 20 are only good in papers right now, unless this model are already in production then that's the time we can asses the features of each planes..but Sukhoi T-50 is already in test flight phase already and they are making progress already what the plane can do..it just a matter of time and what hardware(radar system,electronic counter measures (ECM's),avionics and etc.) will be used to deploy aircraft this and it might give the raptors a run for their money