N540 is 'hotter' than the other Vihtavuori N500 series powders, in fact is probably the highest-energy handloading powder on the market, and that does impose a price in barrel life. In the early days of FTR, N540 was very widely used in 308 with 155s for a brief period - brief because barrels went south in under 1,500 rounds with the heavier loads. As a result, most UK target shooters stay clear of this number even when they'll use other N500 grades such as N550.
Over here N150 and to a lesser extent N140 are used in the 6BR with heavier bullets. We 'lost' all of the Hodgdon 'Extreme' powders last year courtesy of new EU health & safety regulations, but people switched from H4895 and VarGet long before, going back to around 2012, because you simply couldn't get these powders here during the time of powder and components shortages. They soon found that far from being indispensable, there were equally good and reliably available alternatives, many 6BR precision competitors in fact preferring Viht N150. I know it doesn't work for everybody and for some reasons not in the Dasher, and we'll have VarGet users here for many years to come, people building up a precious stash before the EU ban came into effect.
(There are lots of swaps currently going on right now between people with one or two bottles of no longer available grades - I swapped a can of H4831sc for VarGet earlier this year to help a desperate 284 shooter have enough powder to use his existing load in an important F-Class match.)