If you ask me what is better value for money Champagne or Prosecco? I would say Prosecco.
But it’s not a fair question because Prosecco is not the same style of sparkling wine as a Champagne. The better question would be Champagne vs Cava or Crémant.
How the sparkling wine is made
The first step in making sparkling wine is the same. Still, dry “base wine” is produced and then blended with other wines. Then the mixture of sugar and yeast is added. And the second fermentation takes places. For the traditional method, the second fermentation has to be inside of the bottle. Generally speaking only Champagne, Cava and Crémant are made this way. The other option is called Tank method, and it means that the second fermentation happens in large pressurised tanks.
Traditional method vs Tank method
Sparkling wines that are using the traditional method have more contact with lees (dead yeast), which affects the taste a lot. Flavours from this contact are called autolytic.
When you see the picture of the guy rotating the bottles of wine, the reason why he is doing it is to move the yeast toward the neck of the bottle. When the wine is ready, the yeast has to come out. The way how the yeast is removed is called a transfer method.
The traditional way is that the yeast is removed by freezing the neck of the bottle and opening it. The pressure from CO2 will then push the dead yeast out of the bottle. The bottle is then topped up with a mixture of wine and (sometimes) sugar and resealed.
The other way is to empty the entire content into a tank and then filter the wine to remove the yeast. This transfer method is not allowed to be used by Champagne or Cava.
So when you drink Prosecco, it was probably made by the non-traditional way, which is one of the reasons why it’s cheaper than Champagne and why it doesn’t have those intense yeasty (autolytic) flavours as Champagne.