Anyone flying Mig-21's are not much of a force to be dealt with. Su-30's are a much better aircraft (more advanced) but with shody manufacturing, airframes and engines don't last long, it's just a b!tc# when you lose a pilot too. With the litigous mindset in the US, American manufactured aircraft are over safe and last a long time (case in point the B-52). The F-35, though a lesser aircraft to the F-22, is still a formidable airframe with one of the most advanced engines ever. Of course with cutting edge tech, bugs seem to crop up at a pretty regular rate in the first 5 years of a new design, hence the length of time it takes the aircraft to get into service. Those bugs though do get worked out. I remember when I was in the AF we would regulary get classified briefings and part of them were force estimates for segments of our flight paths. Often we would be told XX number of Mig-25 are down at a particular base due to maintenence and the most common fix was engine replacement. It seems that because of the poor manufacturing methods (such as using button head rivets instead of flush head on aerodynamic surfaces) the engines were built for brute force and as such didn't last very long. Numbers like every 4th or 5th mission they would need to be grounded for up to a week for engine swaps. Cheap and fast will sell aircraft but safe keeps very expensive aircrews alive.
