For the past two winters I’ve enjoyed wearing Howard Yount’s lambswool sweaters. They’re of decent thickness – but not too thick – to keep you warm on milder days and add quite a bit of warmth when layered under a sport coat on colder ones. I wore mine quite frequently in the fall over an OCBD and under a waxed jacket and found they did quite well as transitional clothing. The fit is on the trimmer side, but not so slim that they’re unwearable and the quality has held up after a good amount of wear.
Howard Yount rarely has sales or discount codes, but right now quite a lot of items from their fall-winter collection are on sale, including these sweaters, which are now $99 (down from $115) in both crewneck and v-neck form. I think they make great additions for a casual wardrobe.