I have tried bibs from Rapha, Castelli, Assos and now Giordana. With typical Italian tailoring, these bibs in size medium. really fit me (5' 8" 142 lb. 32" waist). I like the different fabric in the construction and the bibs interface with my saddle. The pads work great on long, over 50 miles, rides as well. I wish they fit like the ASSOS but at least the inside feels really soft. The straps are okay, not as wide and not as comfortable as the ASSOS.
I have been using a lower version of the Girodana Bibs for several years and have enjoyed them. I saw the FR-C Pro's go on sale and decided to try them out. When I first tried them on, I thought that the should straps were a little too tight and almost returned them without test riding them. I am so glad that I decided to go for a ride. The shoulder straps went away as soon as I started on the ride and by far this is the most comfortable bibs that I've ever worn. I now have two pair and it is hard to make me put on anything else. I really could not believe how much more comfortable this bib was over the lower version. For me this is my go-to bib.
I have worn Pearl Izumi Pro for years. Tried these on sale due to great reviews. These bibs fit and finish is the best of all the brands I have worn over the years. However, for me the pad density is poor compared to the Izumi Pro. Can feel soreness is sit bones after only 30-40 miles. Never have this issue with Pearl Izumi pro pad. Worn these on 6 rides for 40-80 miles per ride. The left leg band already has some fraying which is also annoying but does not look to be anything that will effect longevity of bib. Would return them if I could. Sticking with Izumi pro bibs. Bib chamois are like bike frame geometry, Personal. Too bad I wasted so much money.....
I have Assos and like them very much. I have Castelli Premio and they are good. Giordana FR-C are the best I have ridden. Of all my bibs, once on the bike I never think about the FR-C's again. They check all the boxes from chamois (never feel the need to stand up and let things recover a bit), to compression, to length, to shoulder straps. My second choice are the Assos, but once I wear them out I likely replace them with more Giordana. Oh sure, I will try the latest and greatest just to see, but the FR-C are the best I have worn. For summer I have purchased a pair of Assos Lite FR-C and they are perforated on the legs for ventilation but still perfectly compressive. For any longer rides, races, fondos, etc., I pull on the FR-C bibs.
After so many rides and many thousands of miles I still found myself looking for my ultimate bib-short and there it is, ... the Giordana FR-C Pro. Outstanding (or would that be outsitting?) comfort along with exceptional form and function led me to owning two pairs.
I used to wear only Pearl Izumi cycling gear but have begun swapping out my old kits with Giordana. They are, IMO, superior in quality for an equivalent price to the PRO line up. The chamois in particular are amazing.
First off, I'm no longer a racer but I train about 3000 miles a year on Zwift, which is a good test bed for shorts. These bibs are a great example of "you get what you pay for". They are supportive with good compression in the legs and the chamois is one of the most comfortable I've worn. I've washed them about 15 times now with no evidence of stitching issues or loss of compression. I will be ordering more next time they're on sale.