A group of us did the Penderyn tour and cery much enjoyed it. Best to go in a group as you each get a couple of tasters, so betwen you you can then try everything. One of our group, a bit of a whisky snob tbh, had been a bit poohey about Penderyn whisky, but after the tour even he acknowledged their current offerings were pretty good. I rather like their Madeira and Sherry versions, some of the others, not so much. One note of interest is their stills are an interesting fractionating column style rather than the traditional pot stills, though they've recently added a couple of those too. Their unique stills were designed by a Doctor Faraday, a chemical engineer who's a direct descendent of Michael Faraday himself. (corrected from Humphrey Davey which I'd misremembered)