If you like the "Under Armor" somewhat stretchy type material, go Nomad. If you prefer the ultralight "flyweight" rip-stop polyester blend type material, then go Ol' Tom.
Both brands are breathable and comfy, but I personally prefer the Ol' Tom. I really like their spine pads in the shirts and pullovers. They used to have thin knee pads in the pants as well but they took those out in the 2.0 pants.