@roger,
Well, their metallurgy was poor in comparison to the Kelts--but they favored the gladius for reasons of tactical doctrine. Because they moved in closely packed ranks, if their line was broken, it was far easier to weild the gladius. When Caesar fought the Kelts in Gaul, and they were rushed by them, weilding long swords, they would press forward to inhibit their enemies use of the long sword. The gladius was in use from the foundation of the city (alleged to have been 754 BCE) until well into the fifth century CE--more than 1200 years. The gladius was made from bronze, and you can hammer bronze to repair the edge without heating it up. Bronze also does not easily corrode. From point of view of maintenance, too, the gladius was superior