basically what they said – short sleeve gives more flexibility with long or short sleeve base layers and arm warmers.
I have a long sleeve (which has been my go-to top this winter) and a short-sleeve which will start to supersede it as it warms up through the ‘spring’, but I still want a wind/waterproof.
There is a convertible version with removable sleeves, but in a recent Gabba thread many people with it seemed to end up just leaving the sleeves on.
They have such a good reputation there’s a danger they could fail to live up to people’s expectations but I was impressed enough to buy a second (I had the SS one first). There’s lots of competition out there now eg. Stolen Goat Orkaan, Parentini Mossa, plus most of the big players have their equivalent, but I saw no reason to risk trying anything else.