My slightly trollish reply: If you have infinite money, it is hard to fail.

Ok, joking aside: If it is considered a failure, what 100B+ military programme has not been considered a failure?

In my totally unqualified opinion, the best cost performance fighter jet in the world is the Saab JAS 39 Gripen. It is very cheap to buy and operate, and has pretty good capabilities. It's a good option for militaries that don't have the infinite money glitch.