I rode across the country twice (averaging about 75-80 miles a day) and I had Cannondale (Vortex and the cheaper version), SheBeest and Pearl Izumi Shorts. I love my Cannondale Vortex (Vertex??), especially because they're a hot shiny blue, and have a line of reflectors down the leg. They're super comfortable, especially the leg elastic.

What I've found, is that, on centuries, no short is really comfortable. Once I started wearing 2 pairs of shorts on really long days (up to 122 miles) I had a happy butt for the whole time! As long as the first pair has a non-chafing chamois, you're set!