Both the common types that have been available recently have been based on German film of the 1960 era.

The Plastic ones are closely based on those used by ADOX/Dupont before the business was sold to the Yugoslavians. They are fairly secure, stand up to dropping without opening, but because the film has to be inserted into an almost closed light trap, the light trap wears and they start leaking light at the point where the light trap hits the lid.

The Metal ones are the same as were used in teh 1960s by AGFA. Ilford also used this style in that era, and it is generaly speculated that they bought them from Agfa. Ilford has admited form time to time that there film packing machines have traditionally been purchased from Agfa. Agfa them selves changed the original design which had the film come out tangentaly, to the current style where it comes out radially. The major problem with this style is that it is fast disappearing. As other have noted later production does not retain the end caps well, and I would speculate that the tooling has become worn out. The version with ISO 400 DX coding is already gone, and Freestyle has indicated that they don't expect these to continue to be available.