Most posters here deriding Russian technology as inferior, is far from ground reality IMO. I am posting this to dubunk the myth that all US products are superior to others by default. I will give reasons for this. US didn't become a world leader by just spending more money. I feel compelled to recite the urban legend claiming that the Americans spent millions of dollars developing the Space Pen, and the Russians instead just used ordinary graphite pencil.
I am sorry, spending more money doesn't mean a thing. I have had the opportunity to work in both Indian and US research institutions. The passion of Indian researchers make up for the money at the disposal of their American counterparts, call me patriotic. But I can vouch that the money spent doesn't directly translate to quality of the product. For example if US spends 10 times more money than its competitor, you can't expect a 10 fold increase in quality. There is a definite edge but its not as much as you would think. US spends a lot of money to lead innovation. But when the concept is there, it is easier to reproduce it (i dont mean reverse engineering or ripping it off). You know which general direction to look for when trying to achieve what others have achieved, you are more confident because it has been achieved. And you dont spend time and effort that the original innovator spent with trial and error. It is no mean feat to be world leaders, I totally respect US scientific community but to achieve the same tech that some other achieved is considerably less costly. WWII, Cold War put humanity on a technological time warp and US has been and still is a great contributor to it.
Also we cant rule out corrupt people in a highly capitalistic US defense manufacturing industry proliferating critical technologies to Russia. You would be naive to think that Russia/US just shut down their tech espionage units after the end of the Cold war.
One more important thing which levels the playing field is the advent of Computer aided designs/modelling. Aircraft development is not as cost intensive as it once was if you have established the basic infrastructure. That nullifies the wealth advantage that US has. Except for critical technologies most other advanced tech can be got from public domain these days. Things are not as secretive in the world scientific community as it once was.
Also the money spent on defense is not entirely spent on R&D. US polices almost the entire world apart from fighting two wars. It takes a considerable amount of money to do that. Russian defense budget doesn't have to include that cost. Also the Russians don't induct as much weaponry as they develop. Russia exports almost as much as US does. Also cost of development is lesser than in the US. All these factors lets them invest more percentage of their defense budget in R&D than the US. So please don't underestimate Russian(for that matter Indian) R&D or just thrash their technology off the cuff.