With the F-22 finally entering service, there
is still a lot of debate over whether the aircraft is worth the cost (about
$400 million each, including the enormous development costs, about $100 million
each without.) About five years ago, the British Defence Evaluation and
Research Agency did a rather extensive, and still largely classified, study
using pilots flying aircraft simulators tuned to represent the characteristics
of various aircraft. The pilots used the weapons and tactics of each nation.
The benchmark was how many Su-35s (the advanced Russian warplane,  then in
development, based on the Su-27) that would be lost for each friendly aircraft.
China, India and Russia use the Su-27, and advanced models of it.



The results of this study were; 



U.S. F-22 10.1 : 1 (10.1 Su-35s lost for each F-22)



European Typhoon 4.5 : 1



French Rafale 1.0 : 1



Russian Su-35 1.0 : 1



U.S. F-15C 0.8 : 1



U.S. F-18D 0.4 : 1



U.S. F-18C 0.3 : 1



U.S. F-16C 0.3 : 1



These results depend a lot on the quality of radars and missiles and, in the
case of the F-22, the effectiveness of stealth technology. Since most details
of this study remained classified, it?s possible that some factors may not have
been portrayed accurately. Except for a few engagements in the 1991 and 2003
Gulf wars, there have been few opportunities to see modern fighters in action.
In the Gulf wars, the Iraqi pilots were much less well trained than their
American and British counterparts.