I've had all three colors over the last eight years (2012 Pearl white Plug-In Prius, 2014 Metallic Gray Volt, 2017 Cajun Red Bolt) ....
White- showed bugs/tar/chips like no other color. Super frustrating front end damage due to rock chips as the plastic nose is made of black plastic which is very noticeable when the white top coat is chipped off.
Red - above conditions were less noticeable than with white, rock chips were still pretty bad, but you had to get close to notice them. Keep in mind, that the nose is made of black plastic under the red top coat.
Gray is the best with all the above, and since the electro-coat primer under the top coat is dark rock chips hardly show on metal parts. Same goes for nose rock chips with the black plastic underneath.
My MY order is for Midnight Silver.