Sprint has announced that it's going to start offering the HTC One in a red color. Dubbed "Ruby Red", the special color of the HTC One is going to be exclusive for Sprint customers in the US. HTC has already started selling the One in red in the UK and is calling the paint job "Glamour Red." That's the reason for the slight difference in saturation you're noticing. The HTC One is also...
Source: http://www.gsmarena.com/sprint_to_offer_the_htc_one_in_ruby_red_starting_august_16-news-6584.php