If you take a look at USSR economic growth over time you'll see that it is very linear with very few accidents. Over the same time period, US economy goes a bit faster by contorting itself into fits and spurts and crisis after crisis.

Some would say that makes the communist economy better, as it's somewhat slower but more reliable and predictable. But capitalists hate it because in a rational economy they can't bet on booms and busts.

So, yeah, it definitely did work and if there hadn't been an arms race and a cold war the Soviet union probably wouldn't have collapsed.