Jeff Croft's comment hits the nail right on the head: "Do you think the aesthetic you guys have developed for your products makes this no-Photoshop workflow ea

Jeff Croft's comment hits the nail right on the head: "Do you think the aesthetic you guys have developed for your products makes this no-Photoshop workflow easier for you than it might for others? ... Is it possible that your no-Photoshop workflow has actually influenced your design style?" It's fine that 37signals chooses to skip Photoshop as a design restraint to increase flexibility and agility, but they're choosing to sacrifice a degree of aesthetic freedom along the way.