I have both the "NATO" metal gas cans (which I bought new) as well as the more modern plastic Scepter Miltiary Fuel Can (MFC) (and I'm trying to buy some of their water tanks as well).
I have to say that having owned both, I actually prefer the true Scepter MFC over the metal ones. To be clear, I'm not talking about the cheap plastic cans you buy at Walmart, etc for $10, these are expensive, but they should last forever.
The MFCs appear to be much heavier duty and I find that I much prefer the screw on cap with its significantly larger gasket vs. the cam-lock lid on the NATO can. I also find the safety pin on the cam lock to be a major PITA. My metal can already has some light rust on the outside after ~3 years of what I would consider to be light use (e.g., not stored outside, it's in a shed).
I have to believe that there are very good reasons for the Scepter MFCs to be fully adopted by the US military as well as the Canadians

and (at least as they quote it), several other NATO countries. They are listed as being safer than the metal cans, which I assume means the potential for an explosion is less than with a metal can (probably b/c it melts vs creating some kind of Boiling Liquid Expanding Vapour explosion with a metal can). I would assume that the US in selecting these things shot them, burned them and blew them up to make sure they met their needs. The fact that these MFC are allowed (IIRC) to be used on military aircraft while full (and the metal ones are not), would suggest there is some difference.
Like others, I have a long line of used, cheap plastic cans scattered across my life with the associated trail of smelly diesel, gas, etc leaking from them. I would have been better off buying three MFCs at $40 each at the start (which is why I'm buying 5 of their water containers now vs. experimenting with all the others).
So, while I think the Expedition Exchange sight is great, I wouldn't take it as 'The Truth' that the metal cans are better.
YMMV.
Cheers, Hugh