I have many Castelli products, including bibs, and generally think very highly of the products. I usually wear an xl in Castelli bibs and ordered that size couldn't get it above my thighs. Returned it for a 2xl (very prompt service BTW). Fits in the torso but the bib straps are much too short and dig into my shoulders. This is strange given I'm not particularly tall at 5' 10 and not overweight (well, maybe 5lbs). Otherwise, appears to have the usual fine quality as other Castelli products.
I am giving a 4 but my heart says 3.5. I assumed they were the updated version of the Velocissimo which I really liked. These feel like the model below. The length is a touch long for my inseam. The chamois is ok but I havent used it for anything over 2.5 hours. There were a few loose threads I had to trim so I cant say the QC is what I expected. The price was fair so its a fine mid week bib.