I own several different Castelli jerseys. All are very good, though fit certainly differs between their various offerings. The Logo series fits me best, that is until I wore the Agnel.
When I first put it on it felt snug around the chest and shoulders, but as soon as I got on the bike the Agnel felt like a custom fit - spot on. It is definitely cut to fit a stretched out road rider, not a cafe lounger. Sleeves are a comfortable length, coming a bit over my biceps and not too tight.
The fabric is very comfortable with temps in the low 90s. I got the black version, so likely won't wear in sunny, hot temps. The styling is sublime. Just about as perfect a jersey as I'm able to imagine.
I typically wear a Large in Castelli jerseys.
Note that I'm 5-7, 190 lbs, 40 inch chest, fairly broad shoulders. Your mileage may vary.