Re: 40% ABV vs. 43% ABV
I agree with Adam regarding the second question. In response to the first one, I think it ultimately depends on the producer and the type of product they're hoping to introduce in to the marketplace. 40% has been a standard for many expressions for a long time, but a shift has occurred where distilleries and independent bottlers are releasing at 43%, 46%, and many even at cask strength. As Adam was referring to, this provides the opportunity for the drinker to have control over which strength they would like their dram to be. In my opinion, as more enthusiasts get excited about things like unchillfiltered and barrel strength products, distilleries will be more open to release bottles that aren't the old, standard smooth 40%. In regards to the EU vs. the states, I'm not sure since I don't have access to European releases, but I end up seeing a huge variability in ABVs across the U.S. when I'm exploring.