It seems like a good number of air forces have kept modernizing and upgrading their Mig-21s. My question is, how good are they now? How would they fair against a more modern aircraft, like an F-16, F-15, Mig-29, or Su-27?
http://en.wikipedia.org/wiki/Mikoyan-Gurevich_MiG-21
http://en.wikipedia.org/wiki/Mikoyan-Gurevich_MiG-21