It’s best not to think about cashmere-and-silk socks that often. Particularly when you’ve built up a good collection of fine merino, in all your favourite colours and the right half size.
Problem is, cashmere/silk is wonderfully luxurious and fabulously practical. The cashmere obviously feels that little bit softer on the skin. Cashmere socks are a pleasure to put on, let alone wear. And then the silk component, normally around 30%, keeps them cool enough to wear in most temperatures and much more hard wearing.
They are very expensive, which is one more reason not to think about them. And I would fervently argue against acquiring just one pair, as an experiment. They will cast everything else into shade.
If you are still tempted, or have the money to consider replacing your whole collection, then I would recommend Bresciani version most highly. Those are they pictured at top.