I can't think of a single revolution that ended with a better government replacing the existing one except for the American one. Russia, Cuba, Iran, etc.. don't make the odds seem likely.
One good example might be the Portuguese Carnation Revolution that took place in 1974.
It overthrew a corporatist dictatorship where private enterprise created a feudal system based on state sponsored monopolies handed out to a few families.
The dictator himself was apparently modest in his life style, but his friends running the monopolies were very wealthy.
Life for the common person improved significantly after the revolution with access to free health-care, more education and better worker rights.
In the short run they got Robespierre. However, in the long run things certainly got better. In the meantime the UK still has a queen and the House of Lords. So maybe having Robespierre was worth it.
You mention Russia, and I'll add China. Both countries were massively feudal and got brought forcefully into the 20th century for one, and into the 21st century for the other, over the course of a few decades. The GDP increases of both countries were astronomical once they settled into state capitalism (early for the Soviet Union, after a few decades for China).
Cuba is a more mixed bag because they don't have the benefit of the massive geographic and population sizes that the previous two countries have, but for the ordinary Cuban, for a few decades, the gains were astronomical.
The seeds of the Iranian revolution were that of a popular, anti-colonial revolt, before it got high-jacked by the clerics and turned into a theocratic shitshow.
The Russian one improved greatly the life of the Russian people. They ended living oppressed under a dictatorship, but it was miles better than starving under the Tsar's monarchy.
Are you trying to be ironic? You're aware that they (and numerous neighbour countries) ended up starving oppressed under communist dictatorship, as opposed to starving oppressed under Tsar's monarchy, yes?
I absolutely agree with you, but it's worth mentioning that communism brought some temporal and local improvements to the lives of some people that is used for arguing for communism. E.g. an individual from a poor family who could study engineering was probably satisfied with the changes. But the big picture is pretty bad anyway.
One good example might be the Portuguese Carnation Revolution that took place in 1974. It overthrew a corporatist dictatorship where private enterprise created a feudal system based on state sponsored monopolies handed out to a few families. The dictator himself was apparently modest in his life style, but his friends running the monopolies were very wealthy. Life for the common person improved significantly after the revolution with access to free health-care, more education and better worker rights.