My first boxes were used vintage kitchen cabinets painted red and John Deere green. Over the years I lusted after a red craftsman box. My wife surprised me with a black Waterloo for a wedding present because she knew that was my favorite color. Red would have been by choice but the black has been wonderful. Now (20 years later) I am building my dream shop and buying all black Home Depot Husky's as they are the closest modern match to my Waterloo. My OCD is making me remove the Husky emblems and scan ebay for old Waterloo emblems but no luck yet.
I really love the Kennedy's. I have collected Kennedy boxes for years (back when you could get them at yard sales for $10) I plan to keep my new shop neat by "displaying" my Kennedy collection but still using them as specific-use boxes. For instance, I use one box as the "Picture/Art hanging supply box" One Kennedy as the plumbing repair box, another as the electrical supply/repair box. It works great and helps me justify having this many boxes. They will look like an art display but be extremely handy.
The only colors I do not like are the Yellows, bright blues, and greens. Just not to my taste. The only thing I know is that serious machinist only use Kennedy boxes. I have friend who are real-deal machinists and they attest that it is a code of most shops.
I have many auto tech buddies and they really don't have a code or color preference. The best tech's boxes are extremely well laid out and highly efficient as most are flat-rate dealer master techs. They are true pros.
Compared to my tech buddies, I clean and polish tools much more than use them

