The chateau itself is well worth seeing as long as you know something about French history and are interested in renaissance architecture, but the cognac side of the tour is disappointing. The still, wine press and processing methods are models and the different types of cognac are explained by synthetic flavours, not the real thing.
I think this tour could have been much better, but our guide was a young woman who obviously didn't want to be escorting a party of ten people over fifty! She was off hand, made no eye-contact, was very dismissive of ( French people's) informed questions and just recited her script. We have been to other similar types of tour, and compared to Moet in Champagne this was not very good. We were fortunate enough to have complimentary tickets, if I had paid 8.5euros I would have been quite cross.
If you are interested in Cognac, you would do better to book yourself a visit with a small producer who actually does the work, you can find them on the Cognac tourist board link.
This review is the subjective opinion of a TripAdvisor member and not of TripAdvisor LLC.