Well-balanced bitter-sweetness dominated by vermouth (hence the name) with faint maraschino but perhaps the most important ingredient is the most hidden...
As someone who's generally not a huge fan of dry vermouth, this was shockingly tasty. I used the easy jigger to measure ¼cl of Boker's (about 4 dashes by my maths) and I definitely didn't regret it. Indeed surprisingly reminiscent of mulled wine