Well I don't have a Gerstner International box, nor have I ever fiddled around with one or seen one in person, but I see on Amazon they don't have the best reviews. I do have a Gerstner and Sons box though. It's an eleven drawer machinist box. I bought it from a guy who was a machinist at John Deere since the 70's and retired from there. His old tools came with the box.
Aside from the dirt in and on it the box had held up amazingly well for being used every day at work for 35 years. He said when he first started working there he bought another Gerstner box, one that was all natural wood with shellac (or whatever it is, I think it's shellac) on the outside but it was picking up too many scratches. He sold that box to a coworker and then went back to Gerstner and bought the same box but with a faux leather covering on the outside of it. That's the box he used until he retired and the one I bought.
When I got it home I took all of the old felt out of it (it was nearly black) and went to the fabric store and bought some nice, new, green felt and contact cemented the new felt everywhere the old felt was. Then I took some Formby's furniture cleaner and cleaned all the dirt and aged on gunk off all the finished oak surfaces (when you drop the front cover, the drawer faces are exposed oak, not leather covered like the outside of the box is).
Once I got all this done the box looks and works pretty well brand new aside from one little section of damage to the leather on the inside of the top compartment. Which is impressive to me because that means the guy used the box for 35 without beating it up and the box took 35 years of use without wearing out either. I know it's that old because while taking the drawers out you could see where someone wrote Feb 18, 1974 in an inconspicuous spot.
If you're sold on having a natural oak box I think you should get on eBay and buy an old original Gerstner and Sons box and clean in up. You should be able to get a good one for $300 or less.