I never bother buying (so-called) Duty Free booze, here’s why…
1.) The really interesting/exotic rums that aren’t exported to Canada are rarely available at the Airport. If you do get lucky and find something cool you can’t depend on it being there next time. They’re selling countless bottles of the usual brands and those vintages don’t interest me so I always buy my rum in advance.
2.) I pack my rum into my checked luggage so there’s zero hassle at security and zero hassle if I have a flight connection.
3.) There’s no sales tax in Cuba so there’s no price advantage to Duty Free. In fact, sometimes I see Duty Free booze for way more money than at my local booze store in Havana. (This might be different on resorts where the booze store has a captive audience so they can jack the prices up, I don’t know.)
4.) At least one airport is confiscating CUCs now (it’s technically illegal to take them out of Cuba) so if you’re not comfortable with smuggling your CUC through security then purchasing Duty Free on the other side comes with yet another hassle and with even more expense.
Bottom line… If you’re only interested in the usual “normal” rum then Duty Free is fine. The plastic Duty Free Bag to seal it in costs an additional 1 CUC. Be sure you get the Receipt placed inside the Duty Free Bag otherwise your bottle(s) could be confiscated at your next destination if you have a connection. But if you’re into something special then purchase the bottle beforehand and pack it into your checked luggage.
That’s my opinion anyway, different strokes…