Thread needs to be expanded as it's quite an interesting topic.
Here's why the MiG-21 was and still is one of the best fighters ever built-
http://www.slideshare.net/mishanbgd/mi-g-21-and-fighter-maneuverability-in-todays-terms
Here's the source material quoted towards the end-
https://books.google.com/books/abou...TICE_Phantom.html?id=vjUcnGdH10wC&redir_esc=y
I think it explains IAF's fascination with the MiG-21 and why it's been so hard to replace. Simply put MiG-21 was the best dogfighter ever built period.
People can quote it's dismal performance in the Arab-Israel conflicts but keep in mind that those were banana republics with equally unprofessional armed forces. Also the fact that the Soviets were a secretive bunch unwilling to divulge professional knowledge to even their own pilots for fear of technological inferiority/ pilot defections didn't help much. Remember that it was due to the IAF's performance in the 1971 war that the MiG-21 gained it's reputation as the Starfighter killer and subsequently became a major export success.
Shortsighted people aka stealth/BVR/F-35 fanboys would never possibly comprehend the above info nor share our enthusiasm for good ol' dogfighters and neither do I ever expect them to. Let these millennial kids live in their bubble. They are waste of our time and endless reserves of patience.