Anirudh S.wrote a review of Castelli Perfetto Long-Sleeve Jersey - Men's on December 8, 2018
Familiarity: I've used it several times
I purchased this on advice of a good cyclist friend of mine. He too owns a Perfetto, and it's previous iteration, the Gabba. I got the Sky Blue color, which looks stunning.
The first time I used this was on a 38-mile fall ride in southeast Michigan in cool weather, and this held up really well in 50-degree F with light drizzle. Subsequent fall-weather rides have been very pleasant, in combination with a SmartWool 150 or 250 base-layer when it gets colder. The base-layer can be a tight fit in size M, especially if you wear a heart-rate monitor on your arm.
I had purchased a size M based on my experience with other Italian cycling clothing (Santini Origine short sleeve jersey). The Perfetto in size M is even more tight-fitting than I expected, even for someone whose arms are as slender as mine.
I'm 5'10" with a 35" waist, 37" chest and weight around 180 lbs. Being south Asian, I have a more slender build than the average physically-active American.
I tried sizing up, but the item was no longer on sale, and I didn't wish to pay full price. I usually wear size S for Pearl Izumi, and M for Santini. I would size up to size L at least for any other future Castelli jersey, especially in their Rosso Corsa line.