They'll be alright, don't get me wrong. Just with so much choice out there, for me it doesn't match the brand reputation is has, if that makes sense?
I'd take the Bolly over the Moet any day, personally.
It is a lot down to preference though, same with most foods and drinks.
With the chilling; you shouldn't store it in the fridge for longer than the couple of hours/hour before drinking it as keeping it in the fridge damages the flavour. Also temperature wise white wine (generally, some varieties do differ) are best served at 7c as any colder than this and it numbs the flavours in the drink.
I like to think you can tell a good champagne as you can allow it to warm without it becoming very acidic and tart. Likewise, you can suffer a poorer bottle by over chilling it, but seems to be missing the point of it in the first place.