There are very few 30yr old cruisers that could make upwind VMG better than a properly sailed Nonsuch, and none easier single or doublehanded. They can outpoint any full keel cruising sloop, but I rarely hear anyone say "don't buy a Westsail, they don't sail to windward". If a Nonsuch has one fault for a sailor, it's that they are relatively boring to sail. The old joke is that a racing crew has three people; helmsman, trimmer, & wine steward! Nonsuches have collected enough pickle dishes in whitesail & shorthanded races to prove their sailing abilities. Their rig just sails & trims differently.I never got them. Don't like the looks. Don't go upwind as well as a sloop. And raising and handling that one huge sail is a huge PITA.
They're not a boat for rounding the Horn or exploring the NW Passage, but anywhere you'd take a cruising catamaran you could sail a Nonsuch, and for a couple do it far more cheaply with almost as much interior living space.