Comfy but tight
I purchased the Castelli Privilegio Jersey a few days and was able to wear it out on the road for the first time today. Although I wasn't on the bike, I did run in it.
First the fit:
It's snug. Im 5'10" 155, 38" chest and ordered the large. It runs tight, especially underneath my arm pits. I would definitely consider this a race cut, unless you went up a couple of sizes from your normal US size. The sleeve length just about reaches the end of my wrists. (My arm length is about 33/34.) The jersey itself is not very long and comes down just below my waist. The grippers around the bottom work, sorta. Since it's shorter on me, it tends to ride up to my waistline. It doesn't bother me too much, but might for others. I've worn other Castelli stuff and usually the mediums are perfect. This was a bit snugger than the other clothing I've worn.
I would say (despite the snugness) it's very comfortable and the fleece lining inside feels good against my body. It's warm but might need a second layer if it's too cold out.
The test run:
The temperature was in the mid 40's and it was the only layer I had on. I only went for a mile a run. The pace was moderate to heavy. The jersey kept me warm and I didn't really feel the cold outside. Castelli has this jersey rated at 59-68 degrees, which makes sense. If I was on the bike today I probably would have wore another layer or jacket. If it was in 50's then I maybe would have worn a wind jacket and think I would have been fine with this. If the temperature was in the upper 60s, then I might not choose this as my primary riding jersey, as I could see it becoming pretty toasty, unless you're riding by the ocean or a damp/overcast day.
Overall I really like this. Its really nice material, the zipper construction is solid and the color is sharp. (I got the black/red) I wasn't going to give this jersey 5 stars because the fit wasn't consistent with their other stuff and I was on the fence about returning it for an XL. However I rated it 5 stars due to the fact it feels really nice and I could foresee this being a solid riding jersey for those mild days.