I have worn Assos S-5 Uno and Mille and GBW Power, Xenon, and Sonic Xenon bib shorts. I completed multiple centuries in Xenon and S-5, and I would recommend either one of these over the different offerings. I found the Mille to be too thick, the GBW Power to be good up to 50 miles, and the GBW Sonic were awesome but I was between sizing.

If you want your chamois frontal to extend upward a ways, go for the Uno. If you have happy with minimum space, go with the Xenon. I personally like the fit/compression and feel of the Xenon the best of all listed above.

Having said this, my go to bib shorts are Capo Limited. The first day out on them I did 75 miles and no chamois creme. The second day I put in 201 miles with minimum creme.