It's funny how our perceptions of Russian technology have changed over the years , when Migs started arriving in the Australian warbird market I heard a lot of comments from engineers saying that in important structural areas the workmanship and design was first class but other less important areas the finish was agricultural , the Russians build tough and effective aircraft.
However for export customers buying new Su-27s or whatever the technical and spares support is lacking and expensive resulting in a lot of aircraft sitting on the ground waiting for parts.