Orange are nice and more uncommon than the reds. True multiple colored rainbows are the most striking IMO but I never see them locally and only rarely on line. The ones on line often look to be photoshopped & can command crazy prices but I'm no expert on the topic.
If you see a rainbow in person, the price is reasonable and have confidence in the seller, I'd grab 'em. You can get the reds, greens or oranges another day.