The thing about wines above £20 or so (and certainly in the £100 bracket) is that the taste can become a very personal thing. One of the reason wine snobs like expensive wines is that they have become accustomed to the slightly odd flavours that such outrageous expense brings.
If you are used to wines in the £50 bracket, then you will know the answer to your own question. If not, then it depends on your criteria for selecting the wine.
Are you trying to impress with the label? That's a perfectly legitimate reason, in which case, either the Krug or Dom Perignon.
Are you looking of some objective mark of quality in which case the DP vintage is likely to deliver the goods. Champagne growers only declare a vintage in the best years, so any vintage wine is likely to be better than a non-vintage (NV) wine.
Are you trying to get a wine that will be pleasant to drink? In which case, any of them will be absolutely fine. I used to drink a lot of Veuve Clicquot back in the day.
All Champgne houses seek to blend wines from different years so that the drinking experience of the NV brand is the same from bottle to bottle (of any given brand) and from year to year.
Personally I wold not choose any Champagne either for home consumption, or at a restaurant, the prices are just silly, and I have become less impressed by brand names over the years. Get a good-quality Californian, NZ or Australian fizz that uses the same grapes for an experience that is just as good, at a much better price.
Chassagne Montrachet can be lovely with huge depth, a slight bitterness on the end, that you rarely get with the new World Chardonnays - but be sure that the vintage is a good one. If spending £50 ish on a bottle I'd defintely prefer to spend it on the Burgundy than the Champagne.
If in further doubt, ask the waiter/sommelier what will go best with the food. They should know more than to just up-sell.