I have used Assos for years, and always used to swear by it. It always used to be worth the extra for fit (which in theory any other brand could achieve but never used to) and quality.
Castelli have certainly matched them for fit now.
And in terms of quality, Assos just doesn't last as long as it used to. Interestingly, reading the little card that came with my last Assos, this is intentional. The materials they use now are engineered for performance, not longevity. So, it's great, while it lasts, but it doesn't stand up to the rigours of repeated washing and wearing as much as it used to.
Also, being quite tall, Asos shorts now come up too short in the leg. They always used to, but the higher up the Asos range you go, the shorter they seem to be. To the extent that I switched to their 'knickers' (3/4 length)
I have switched to Gore (top half) and Castelli (bottom half).