Re: J-20... The New Generation Fighter II
The comparison should not be made alone on the basis of what the silent eagle concept can do, but rather on what options the countries (to which it is being pitched) have?
What other options are out their for the countries looking to upgrade their fleet? For west leaning nations like south Korea, japan etc, the Russian aircraft are complete non-starters. That leaves the F-35 as the only stealth option out there. And if a country is not a partner in that program that ...well its the Boeing plane or nothing. And no matter how many concepts japan and South Korea display, they have no proven capability of designing airplanes.
So for nations desperate to counter russian/indian/chinese next generation planes and not having access to F-35 there are not that many options.
I don't see why South Korea couldn't buy planes from Russia. Didn't Su-35 or some other Flanker variant enter South Korea's contest for a strike fighter (F-15K came out on top)? Russia is a major provider of rocket components for South Korea's Space Program so I don't see why not.
As for Japan's capabilities for designing planes... ever since WWII I think they've only created two indigenious designs. The F-1 fighter bomber and the F-2. I personally find it funny how the same people who call the J-10 a Lavi ripoff also believe the F-2 to be an independent design. No, don't get me wrong, I think that Japan has a fantastic aviation industry and is one of the top fighter aircraft manufacturers in Asia. It's attempt at designing new planes, however, hasn't been entirely successful. The F-2, which looks impressive on paper with its AESA radars and what not, costs an incredible amount for what is, essentially, a F-16 upgrade.
As for the ATDX stealth fighter project I'm of the opinion that Japan could, without a doubt, pull it off. However the more I look at it the more it looks like an attempt to "fish" for the F-22. In the end I think Japan would be satisfied with the F-35.