We've got second hand information for all of them, very little of what they actually said about themselves. We know Sparta the best, because Athens admired Sparta the most, and because of the Peloponnese and Persian Wars interacted with them the most as well. Most of what we have about the rest is very loose, so we cannot know their ethos. There are a couple unsung greats among the Greeks, however.
But, some historians think Thebes, who worshiped Dionysus in a similar way that Athens did Athena and Sparta did Ares, had the second best hoplite formation in Greece behind Sparta, and would eventually play a significant role in crippling Athens in a supporting role to Sparta, before playing a pivotal role in crippling Sparta. Thebes had a brief stint as the preeminent city state, helped tutor Philip, father of Alexander, and had the sacred band of lovers.
Corinth, by contrast, was a more oligarchic version of Athens, an ally of convenience always working against the most prominent player in Greece, and seems to be the most Machiavellian/Hobbesian of city states, and were able to maintain their position through trade from both axes of the greek world. They also happened to be the mother city of Syracuse, and worshiped Poseidon.
Syracuse was the strongest of all Poleis, if some can be believed. They worshiped Athena as their city's deity, the Syracuse had a mixed relations with Tyrants and brief stints of almost democracy, but it died as a Tyranny indistinguishable from a monarchy.
Argos's eternal rivalry with Sparta is also something that shouldn't be discounted.