While the question of whether Sparta was better than Athens is slightly subjective, it's possible to consider Athens inferior because it fell victim to the temptation of becoming an exploitative imperial power. By contrast, Sparta led an alliance commonly seen as relieving other Greek states of the burden of Athenian hegemony.
After the Persian Wars, in which the Greek states were ultimately successful, Athens arose as one of the primary military city-states and as the dominant naval one. In the ensuing years, Athens concentrated its power. Beginning in the 470s B.C., Athens formed the Delian League, a cooperative of Greek cities allied for mutual defense and for the protection of Greeks elsewhere in the Mediterranean. As time wore on, however, the Athenians transformed the league into an instrument of coercion, eventually even moving the league's treasury from Delos to Athens, where then Athenian leader Pericles ultimately used the funds for vast urban building projects, including the construction of the famous Parthenon.
By the 430s B.C., Athens' imperial ambitions had become egregious enough for some of its allies to consider defection and for the now rival Pelopponesian League, led by Sparta, to appear as a liberating force, poised to disperse the Athenian menace. During the ensuing Pelopponesian War, Athens continued with its imperial disposition towards potential allies. For example, it infamously destroyed the city of Melos when it refused to swear loyalty to and alliance with the Athenian war effort. By 404 B.C., Athens was decisively defeated, and the Spartans acted as custodians of the city's government, disbanding the Delian League and ushering in the period of the 30 Tyrants.