The bottom line is that Champagne is the biggest marketing rip-off in the history of alcoholic drink.
A good Spanish cava or Italian prosecco is just as good as any champagne and regularly perform just as well in blind tastings.
Equally some cheap champagnes are just as good as those costing many times more.
All these drinks are merely common blended grapes with fizz added - it's only hugely exensive marketing,product placement and aggressive legal action to protect the brand which gives champagne its cache.
That said, I am partial to a bottle of Pol Roger in the Savoy's American Bar with an old chum of mine, every time I'm in London.