I don’t know, not being a Scotch drinker.
But I do enjoy a Grand Marnier periodically after a fine dinner out, and having had the regular, the 50 and 150 year old Grand Marnier, I will say that the 150 year old stuff is smoother than silk and waaaaay more interesting than the younger stuff.
How that translates into Scotch, I have not the slightest idea.
BTW, I don't think there is a 150 year old Grand Marnier. It was invented in 1880. And according to this site, probably not.
The next level of Grand Marnier is the Centennial Edition, or Cuvé du Centenaire, which is made using the same technique as the Red Label, but substituting 25-year-old Cognac for the normal Cognac used. This type of Grand Marnier costs nearly 200 US dollars (USD) per bottle and is meant to be drunk on its own. At the top of the heap is the Grand Marnier 150, a blend of Grand Marnier made using the highest-quality 50-year-old Cognac. It costs in excess of 200 USD per bottle and is often very difficult to find – indeed, an advertising campaign for it used the line: "Hard to find, impossible to pronounce, and prohibitively expensive."