Brakepads and rum-soaked raisins: yup, that's PX alright. Pretty oily and velvety nose, though, purrs like a kitty. The farmy peat that is characteristic for smoky Benriachs is tamed by syrupy, sweet, wet-cask-delivered sherry. Very sweet, very full, dark, and massively herbal. Notes of dark stout and/or Marmite. Kind of like a more mature Laphroaig Triple Wood, or a less strong Ardbeg Uigedail, but the peat smoke is herbal, fungal, and musty instead of maritime, brackish, and salty. It's very successful in what it sets out to do, but I find it a bit vulgar and over-the-top.
The attack could be more impressive; initially, the mouthfeel is not nearly as oily as the nose would have you think (the oiliness returns with a vengeance at the death, though). Otherwise, the palate delivers exactly what the nose promised: oodles of saccharine, syrupy sherry dripping from a skeleton of dry, peppery, musty herbaceousness. A real bruiser; one shudders to think what this would've felt like at cask strength.
The finish is predictably long, sweet, and smoky. In a word (or rather two): cough syrup.