I consider the wide-scale and fairly high-quality scientific education system to be the only genuine upside of Soviet communism. Admittedly, part of its success was the fact that it offered many people the only way to the middle or upper class (the Soviet Union was an extreme class society, with peasants forced to stay on their collective farms and non-Muscovites banned from settling in Moscow unless they took up professions that were currently desired by the system). Another caveat is that it was STEM-only, and excluded computer science (which the Soviet system was unconducive to for various reasons) until the 80s. The SU was particularly unwilling to teach anyone foreign languages, unless one chose (and was cleared) to work for intel.