I first discovered this when buying a bottle for my birthday - it came highly recommended by the shop attendant and was a nice complement to the Compass Box Great King St. Artist's Blend. The Artist's Blend was a big hit until we opened the Springbank 15, which blew everyone away with its depth and complexity. I didn't see anything about rum cask maturing on the bottle, but I've read that it is in fact rum matured, like the Balvenie Carribean Cask. The difference being that the Balvenie is 43%, and this Springbank definitely benefits from the extra ABV at 46%. The Springbank is non-chill-filtered as well, which is something I always look for in a scotch. And, finally, there is no colorant added. Too many scotches are chill filtered, lower ABV and have colorant! Keep an eye out for these 46%, non-chill-filtered, no-colorant scotches as they are often quite good, and the Springbank 15 is no exception. Absolutely delicious!