The square box tool box is MUCH larger than the 'contoured' (and more aesthetically pleasing) box sold by Mike's. In wanting to Keep my '28 Phaeton as stock as possible, I chose Mike's 'Contoured' box for it's looks, even though it holds much less tools and supplies than does the square box one.
On the other hand for my 1931 Coupe, built up as a daily driver 'Touring A', I was less concerned about original appearances. So for that car I installed the much larger capacity Box type. I have had this larger square box in service for over thirty years, and I LOVE it. With careful packing, it holds a huge assortment of items. It was especially useful when I drove from California to Alaska and back. I believe that these type of front-mounted tool boxes are still available at some of the Parts Suppliers.
Additionally, the square box that fits snuggly behind the front bumper, makes an excellent sitting chair for frequent 'fireside chats', as well as a handy shelf to set stuff on while parked.
So having and using both types of boxes, if I had to choose only one - it would be the square box. Once you get past the fact that it does look like an 'after thought', it is infinitely more useful.
P.S. - Do be mindful, that when you install either box, you lose the ability to access your crank hole, and thereby you lose the ability to use a hand crank to turn over your engine - for timing, starting, etc.
- Doug Vieyra, Eureka, California