Opinions will probably differ on this Gear of the Week. Some people don't see the point of a vest and prefer to take a proper midlayer with them, especially on multi-day tours. I can understand this opinion, but I disagree. I like to wear a vest over my base layer on ski tours in the current temperatures, for example. It warms the chest area and protects against the wind, but also offers good ventilation thanks to the lack of sleeves.
I've owned the Smartwool Smartloft vest since the beginning of winter, so it's probably been in use for over 40 days, in the house, at work, chilling out, ski touring, cooking, pretty much every activity except going to the sauna at home😉. I am 186 cm tall, weigh 85 kg and wear the vest in size L.