Key differences:

There's a 2-seater planned for the T-50;
The T-50 has a slightly larger (78.8 sq. m. against F-22's 78.04) and better-loaded (330 kg/sq. m. against 340, max. 470 vs. 487) wing, which makes it more agile in dogfight, combined with...
3D thrust-vectoring engines (Saturn Make 117 - no…

Next-gen Russian/Indian stealthy fighter prototype. Roughly equivalent to F-22 by specs, but slightly larger, with a larger weapons bay and more complex aerodynamics. Oh, and 3D vectored thrust engines (superior agility).

Su-27 prototype.

Prototype of the Blackstar in Pyromania.

Su-37 engine, 3D vectored thrust nozzle.

Su-27 showing off vertical acceleration (high thrust:weight ratio, the plane can accelerate climbing).