Clayton D.wrote a review of Castelli Pro Fit Light Rain Jacket - Men's on January 6, 2019
Familiarity: I've used it once or twice and have initial impressions
This jacket seems very nice. It is pretty much as described above (aero), while not being quite as small in fit as some other Castelli jackets (the Cross Warm-up jacket is quite a bit smaller overall and the RoS jersey is a bit more tight around the shoulders and neck).
This Pro Fit Light Rain Jacket is made in Romania, and seems to fit like other Castelli items made there: normal to longer in length and slightly tight overall. The upper arms are a bit snug for my liking, but they may stretch out some. The actual shoulder opening does not bind under the arms like many Castelli items that are made in Bosnia which can cause circulation problems, it is just the sleeve tops that are tight for my arms which are slightly large for a 140 pound cyclist. This is more of a comfort-only issue here. I may end up converting it to a vest if they do not stretch out some though. It is much more packable than the thermal Gabba vest, so would fit much easier in a jersey pocket when needed.
I haven't yet worn the jacket in rain but do not doubt that it should be sufficient for light to mid rain.
I am 5'9", 140lbs. and the medium fits me well (with the slight exception of the upper arms).