I have found the Castelli shorts to be far more comfortable than others I have worn. They do run about a size smaller than others. These provide more compression on my legs which helps on longer rides.
Good quality bike shorts (and bibs) are hard to find. I am glad I found the Endurance X2 shorts, I have several pairs. I think they are the best no-butt-lube shorts out there. Hopefully they'll keep making them and find and replace them with something better !!
Shorts run small, so I sized up one size. Shorts and chamois mold to the body to provide a comfortable ride with full cushioning. Also, the shorts wick sweat away from the body amazingly well...
I recently used these for a century ride and they were very comfortable. But they run small. I had to return a Large and re-order an XL when the sizing chart indicated a Large.
I bought a pair of these shorts and then immediately went out and bought another pair of them (bib shorts style). So comfortable on long training rides or centuries. I also like the way I look in these shorts. Better value with comparable comfort to Assos shorts. Unique chamois is the key to the comfort of these shorts. The fit is snug so if you want extra room in the shorts, you may want to order a size larger. I like the snug fit on my legs but others might like it a bit looser.
I have been buying the Castelli Velocissmo short for years and really think it hits the value/comfort mark. I usually get a couple seasons out of a pair in heavy rotation with a couple other pairs and thought to upgrade to the Endurance X2 on the last order. While this is still a very nice pair of shorts, I don't find them any more comfortable than the Velocissmo. But of particular consideration for some people is that the Endurance Short runs about a 12 size smaller than the Velocissmo. So if you ever found yourself in the middle of some sizes this may be a plus for you. But if you are a solid medium, for example, in the Velocissmo, you might want to size up if you want to try this one.