I notice that just like us amateurs and wanna-be's they have all sorts of personal preference going on.
Some have bikes that look like the size they must have rode when pre-teen. Some have oval-chainwheels, C. Froome being notable for using them. Some with wide handlebars others with narrow handlebars.
It'd be really interesting to know what size chainrings and cogs on the back they are running between each rider.