Tasty! With the cinnamon, it almost gives me a "cider" vibe, so I think this would be particularly enjoyable in the autumn (but also any night of the year...). Nice to have an atypical cocktail made with dark/black rum to add to the roster!
I would definite agree that this was on the sweet side as is. Recommend leaving out the rich syrup. It is not really needed with the sugar/cinnamon rim. Other than that, the flavor combinations are just fantastic. The cinnamon goes remarkably well with the Black Seal rum.
Just had this as our first World Cocktail day drink and we were very pleasantly surprised. I didn-t have cinammon powder per se but had ginger bread powder which contains mostly cinammon and I think it made it even better, the aroma when bringing the glass to the mouth was wonderful. So I recommend not to skip the rim step (even with plain cinammon)