For warmth, no cold spots in construction, and comfort for base riding in cold these are very good tights. Pricey but worth the extra money compared to less expensive brands - at least as far as keeping the cold out, which is most important to me. But the cost does not include the Hand of God pushing you at 40 kph.
I love these tights! I've been riding them for a couple of months, and they are wearing well. Great compression without being constricting, nicely cut for comfort, mercifully generous chamois, wide straps mean they seat well and never cut your shoulders, plus long enough to keep me warm to the tops of my socks - unlike my PI and Castelli tights that leave me some very chilly real estate around the ankles.
A word on fit - Assos cuts their tights to fit right in the riding position, so standing up they feel a bit off. But as soon as you are in the saddle, you realize how well designed they are. Assos recommends that if you are unsure, go with the smaller size. I am 6'2", 178 lbs, and on the cusp of L/XL. L works perfectly.
A word on temperature - I am riding in the SF bay area, so "winter" here is really just chilly, not actually cold. These tights are perfect for temps in the 40's-50's. However, for colder weather you might prefer their warmer gear.
They are not cheap, hence the 4 star on value, but ultimately, these are indeed worth the price.
I've had a few rides in these and so far am very happy. They are well cut, especially when compared to the other tights I have used - PI and Corsa. PI tend to be saggy and a bit short, and Corsa are just way too short in the leg giving me freezing ankles. Unlike the other 2, the legs are very long, reaching all the way to the top of my socks, and do not rely on a zipper to let your feet in. Instead the lycra is quite tight, making for a fantastic fit. In fact, across the entire tight, the lycra is satisfyingly snug and springy. The shoulder straps are quite wide (~2") which makes them awkward to put on but extremely comfortable to ride in. As with their bib shorts, the cut is designed to fit optimally in riding position, so when you are standing up and walking around they feel a little awkward, but the ride is super. The pad is very thick which provides a lot of comfort. However, it is also a little big, so it takes a little shifting around to get it just right.
I'm riding in pretty mild 'winter' conditions, and have been entirely comfortable in the 40-60 F range. I'd typically wear shorts at 60, but some days heat up more than expected. If you are in real winter, you might want to consider Assos's warmer model.
For reference, I am 6'2", 175 lbs and L fits perfectly. I also wear L in PI and Corsa (for Corsa I should have gone up a size).
The only minus is the price, which is quite steep. All in all, I would happily buy these again.
This is my first pair of Assos tights and I am not impressed. Given the cost, expected angels to grab my buttocks and carry me around. Alas, it was not to be. The moving pad doesn't do anything and seems like a total gimmick. I don't like the super wide shoulder straps and the quality of the material is just average. They are nice shorts and I'll ride with them, but they aren't a good value.