There are some discussions about Lenin and Stalin's views of science and the state here, and the impact of Stalinism on various sciences here. The short answer is that under Lenin, famous Akademiks (like Pavlov) were given leeway because of their fame and prominence, and because Lenin did consider science to be of extreme importance for the future of Soviet Communism. At the same time, new ideologies about science and the state were being put in place. Under Stalin, all academic work was deeply politicized, though sometimes in unpredictable ways that could vary dramatically by field. Some sciences (notably biology) suffered terribly in this political environment, some were basically fine (like chemistry), but all were part of a larger totalitarian society and that meant being subservient to the needs of the state. After Stalin some of this cooled, though it took some time before many of these things normalized, and even then, scientists still operated within the constraints of the Soviet state.

In terms of the quality of education, my sense is that it is was a mixed bag. On the one hand, the Soviets brought far more attention to technical education, and far greater access to education, than had existed in Russia beforehand. They did truly build the Soviet Union into a major scientific superpower of the world, something that did not really exist under the Tsars. They made considerable effort to find talent wherever it was, and to use it. Sciences that were connected to the state military-industrial complex were well-funded and afforded many opportunities. They went so far as to create an entire city in Siberia dedicated to scientific research (Akademgorodok). They did truly take a second-rate scientific state and turn it into a first-rate one, though I am not saying that as any endorsement of their methods or system.

On the other hand, all of this work was done in the aforementioned totalitarian atmosphere, with definite limits on what kinds of work and conclusions could be pursued, and scientists lacked the kind of autonomy that would be more associated with the West (although there were often limits there too, as well, during periods like McCarthyism; it is important not to hold up a somewhat mythical view of the freedom of Western science as the foil). Additionally, there was a lack of autonomy even in the late period with regards to future careers — a technically-trained student could be essentially drafted into a needed career path, whether it what they desired or not.