The MiG-21 was smaller and lighter and fast but not as easy to fly. It was a high performance jet but didn't necessarily turn the best with the delta wing as it bleeds airspeed too fast and the way fuel was used it would could be difficult to control when at 2/3 fuel used.
India lost a huge amount of their MiG-21's to crashes etc. from poor training. Not having any jet trainer aircraft coupled with the MiG-21's high performance and more difficult handling has led to them losing most of them.
