The soldiers of Massalia began using Celtic-style longswords and occassionally other pieces of equipment. They fought, otherwise, in a manner more typical of Hellenic soldiers.
Massalia is a city in an interesting position. It is a Greek city, but with a substantial Celtic population and relations with neighboring Celtic tribes. Its soldiers have adjusted themselves with some Celtic gear to make them of greater use in a close melee if the phalanx is abandonned. They make use of a superior Celtic longsword in close quarters, able to handle themselves better in such situations compared to others with lesser weapons.
Historically, Massalia was home to a substantial Greco-Celt population who were attracted to the temple of Herakles there. The inhabitants of Massalia remained largely Greek in culture, but trading, intermarrying, and fighting with nearby Celtic tribes led to crossovers in the equipment carried by each side. The soldiers of Massalia, for example, began using Celtic-style longswords and occassionally other pieces of equipment. They fought, otherwise, in a manner more typical of Hellenic soldiers.
These men are basically Hoplitai (Greek Classical Hoplites) armed with lethal swords, they are quite capable against both infantry and cavalry as a result, as well as having a disciplined and a solid formation when in guard mode just like a hoplite. For a unit with average costs, they are good unit to have, whether as recruitable units or mercenaries.