Whenever I hear of a new company engaging Arashi as endorsers of their products, my eyes go bright, and a brief dopamine surge kicks off in my brain as the anticipation buds. Over the years (and I've done a couple of posts on Arashi CMs
here and
here), the fab five have acted as endorsers for various products, from cars to potato chips (and even diapers, in MatsuJun's case), and even though I don't have the opportunity (or necessity, really) to purchase many of the things they endorse, I still hang on to every frame of their CMs because 1) they're beautiful; 2) they're action-packed; 3) they're humorous; and 4) they always have a happy ending. It's the plastic world of commercials, after all.
I've found that different companies tend to make use of Arashi's image in different ways. For example, Kirin likes to play the OT5 card a lot (perhaps, they feel the completeness of Arashi most keenly, since they were a company who didn't start out with all five members in their initial contract, and had to acquire Nino and Sho after the other three). Kirin's CM's also tend to be light and jovial, which is undoubtedly meant to evoke the frothy, fizzy feel of their beer. Nissan, on the other hand, tended more towards making Arashi look sleek and modern, which of course fit perfectly with the intended image of their sleek and modern cars. In contrast to most others, JAL likes to hover closer to reality, collaborating with Ohno on a jet design and often referencing Arashi's real-life duties as idols in their CM scripts. Hitachi, the other big corporation with all five under its name, places the heaviest emphasis on comedic elements and often casts Arashi in various domestic vignettes to showcase that.
Starting a couple of years ago (2013? 2014?), a new player signed on to deck itself out in the five-colored rainbow, and this was Gungho, the company that developed the popular smartphone game "Puzzles and Dragons" or "Pazudora" for short.