It must be a resounding success - the UK is about to commit to buying some - like we committed to buying Skybolt and the F-111 (cancelling the awesome home grown TSR 2 in the process):

http://en.wikipedia.org/wiki/BAC_TSR-2

No, at this point we should have built more F-22s for air-to-air. Strange how the "cheap" program is now the expensive one.