Went to Deanston Distillery last week in Scotland, it is very close to Stirling Castle if you're around there.
I've now been to three Whiskey distilleries, and in chronological order:
1) Jamieson in Dublin - It's now just an exhibition than a working distillery. That said, someone has invested a big chunk of capital in making it look nice, and there's a very good script and interesting exploration of some of the facilities and processes in making whiskey. The "tour" was delivered was delivered by a university student who spoke well, but didn't seem to be much of an expert. Each tour had a large group of 20 or 30 participants.
2) Bushmills up in Northern Ireland - A huge facility, with an outstanding tour guide - a 60-something year old master distiller, who enjoyed telling stories from the 70s and 80s.
3) Deanston - A middling facility, with a middling tour guide. Was pleasant and fun with a smallish group, but not deeply memorable.
They did have some a nice little bonded warehouse though: