The St.Magdalene 1979 that the MM's are celebrating is a Rare Malt bottling from Diageo. It's ABV is 63.80% and it's truly an amazing dram.
I've tasted a 21 yrs from OMC, and it doesn't even get close to the 1979. It's a very spicy dram, that can take a LOT of water. It get's spicier the more water you add. But of course, that's a matter of opinion...
As discussing bang for the buck, I must say, It's worth every pennie. It's one of the cheaper RM-bottlings. Approximately 100 Euro.
I included this dram in a blind RM-tasting (six different RM's, one a Port Ellen from 1978), and this bottling came in second.