Since Egypt has ordered 50, it is likely that it is a counter to the F-35. Russia have ordered a first batch of 37. According to Wikipedia they are planning a fleet of 170. They always put more emphasis on missile systems instead of fighters.
The Russian war machine hurts because a lot of the design work and parts are manufactured in Ukraina. And they need advanced Western components which now are restricted. Suddenly the Krimean annexation and fighting in the East does not look particularly smart : No spare parts for you Mr. Putin.
And before you ramp up the F-35 Godspel : When there is war there is extensive ECM. And it is downright dangerous to emit much. Everybody’s radar range is down to what it burn through. So everybody will rely on IRST. And then suddenly, the Stealth advantage has largely evaporated.
Nobody talks much about what happens when the ECM system dial reads “War”.