Remembering both vermouth and gin are flavoured with similar botanicals, they obviously have an affinity for each other. This drink may be simple but made...
Just tried this again (with Antica Formula and a mainstream gin) and it showed its class, as it always does. Such a simple drink to construct, I reckon it gets overlooked in favour of more glamorous martinis and manhattans. But it's a true classic, an absolute beauty.
I've just been rereading David Embury's 1948 classic, 'The Fine Art of Mixing Drinks', and it suggests the great man was no fan of the Gin & It. He says: "...there is always likely to be something wrong, something not quite satisfactory, about a blend either of dry vermouth and whisky or of sweet vermouth and gin."