When you want it to last and to be watertight I don't think you can beat the "ammo can". The only ones that I have seen damaged are a few that had a run in with a mowing machine used by road crews.
I sand off any rust and re-paint them inside and out. These cans should last for years and years. It is easy to bring a can of WD40 and a can of spray paint on your yearly cache maintenance run.
I have 4 Folgers Plastic Coffee container caches,painted in the local cammo and sealed with indoor / outdoor clear spray. They've been out all summer and fall and they have held up well. The only one I had a problem with is the one a critter tasted. !!!! I am leaving them out this winter to see how they fare. One suggestion is to place them where they can stand upright, letting the cover do it's job.
Yeah, I did an Airborne medication (over the counter) type plastic container, but reinforced it with "Gorilla" black tape. Very heavy stuff. It had a good snap shut, but will watch it this winter to see that it holds up. I live very close by, so that one's easy. Other than that, I'm either doing magnetic nanos (no real winter issues there) or the ammo can.
But I'd still like to try a "dip" container - chewing tobacco cleaned out obviously. I might just give one a whirl - I have like 10 of them saved up by now. If they work well, that'll be awesome, until my supplier stops chewing!