Right from the start you can tell that Boris enjoys what he does, immensely so. We were with a slightly larger group of 18 people of different age groups, and Boris made sure to include information relevant to everyone.
The venue is a 300 year old cellar, the wines are (almost) all Slovenian, save one, and the actual tasting is not as high brow as you would expect. People come here for a fun 2 hours (2.5 in our case), and Boris delivers that in spades.
Highly recommended, try to do it at the beginning of your stay, then you will have a better idea of what wines to orde in the local restaurants.