I had a glass of Louis XIII Cognac a few years ago and was really surprised at how much better it was than a VSOP. As you say the tail lasted so long and was so rich and complex, I didn't expect it to be that incredible.
Whoah! Haven't had one yet. Saving that until I make a lot more money! :)
But on a more affordable level I recommend checking out https://www.cognac-expert.com. They do have the incredibly expensive stuff, but at a also a reasonable-price range that goes well beyond the standard Remy, Hennessy, etc. VSOP or even XO. A world to explore!
Looking at that link it's a scary and expensive hobby. Having said that my brother used to get my dad a £200-500 bottle of scotch for Christmas each year so definitely something to explore. Cheers.
