Similar to wine, Cognac has very specific law governing what they can put on the label. There are sub-regions within Cognac, including Grande Champagne, Petite Champagne, Borderies, and 3 lesser regions. Grande Champagne is considered as the best region in Cognac. The "Fine Champagne" in the label means that all the grapes were from Grande and Petite Champagne regions, and Grande Champagne has percentage higher than 50%. In very few cases you will see label stating "Grande Champagne" which means more than 90% (or 100%, I forgot) of the grapes were from Grande Champagne. Remy's are Fine Champagne and Hennessy's are just plain Cognac.

Borderies is an interesting region. It's very small and is said to have delicate floral aroma. I know that Otard XO and Napoleon are blended with Borderies but never have it yet.

I've had some small production Cognac and loved them. Pierre Ferrand is one of my favorite. It offers different level of Cognac from VSOP equivalent to vintage cognac.

Pierre Ferrand's are 100% Grande Champagne even for its VSOP. Another small production, Chateau Fontpinot, is also 100% Grande Champagne. I've had its XO - very good but maybe too smooth. It's about the same price as Remy XO.

I have one 1962 vintage which is very rare, and much much better than any XO I've ever had, if not as sophisticated as Louis XIII. I'm not sure if it is still available, or how much it costs. I bought it 10 years ago at NYC for only around $150. Similar offerings from Pierre Ferrand vintage cognac are definitely great recommendation for under $500.

Those big-house congac brands all offer special blend above XO, and much more expensive. I haven't had opportunity to have those but believe that they are superior to their own XO. My personal favorite is Remy Martin's Louis XIII but it costs more than $1K for 750ml. It's a kind of ultimate Cognac experience - there is nothing more expensive or sophisticated.