Don't get me wrong...I love shopping for great wine values at all price levels...I often buy excellent wines at less than $20, but if I had a $50 or $100 budget, I think I'd generally be able to do better. I think other airlines with bigger wine budgets do generally have better wines. I think the BA selection (including champagne) is upper-medium. I did really like the Bollinger Grand Annee in years past. I will admit that I do like DP (I'm sure my tastes will be criticized for that.) Now...I wish they'd bring back the caviar to go with all this generally good bubbly (although BA has had some pretty poor stuff in years past as well), but then again, I wish they'd bring back the Concorde.
I also agree that you should be able to get a better wine for $20 from a place like Argentina than from California or France. I generally enjoy Malbecs for that very reason, and the Cantena is nice.
But I still say, give me a $50 budget and I'll beat the Cantena every day (that's not the same as saying every $50 wine is better than the Cantena).
On a related tangent, I do appreciate the availability of JW Blue, not that it's my favorite "premium" whiskey (as in $100-150+/bottle) -- unlimited free Blue Label is a nice treat.