jay106001480-0wrote a review of Castelli Alpha Ros Jacket - Men's on November 10, 2017
Familiarity: I've used it once or twice and have initial impressions
Pros: Dual layers for easier temp moderation.
Cons: Many sewn parts that are prone to fail. Not as warm as expected. Inner layer not removable.
Fit: Form fitting closer to race fit than casual fit.
Summary: I purchased this specifically for riding in colder temps (< 32 degrees). Tried it out this morning and it was exactly 32 degrees. First 10 minutes I was cold. After some moderate pedaling, I warmed up to a comfortable temp. My base layer was an Under Armour ColdGear Evo Long Sleeve Compression Mock. Any temps lower than 32 degrees and I'd consider another layer.
By comparison, I also have the Senza 2 jacket. The Senza 2 is definitely more bulky and more of a casual fit, but it feels warmer. The Alpha ROS does have the benefit of unzipping the outer layer for more temp moderation.
Overall, I wish the Alpha ROS was warmer, was more of a casual fit, and didn't have so many sewn pieces that will eventually fail. Would I purchase it again? Probably not. My biggest concern is the durability of all the sewn pieces.