Every agency in this market lists the same capabilities. The differences that determine the outcome are structural rather than technical.
The commercial model shapes the advice
An agency on a fixed retainer is paid the same whether or not revenue moves. An agency paid on a share of growth has a direct interest in telling you uncomfortable things about your pricing, margin or fulfilment. Neither is dishonest; the incentives simply differ, and incentives shape advice.
One accountable team beats three specialists
When the developer, the marketer and the systems integrator are separate companies, problems land in the gaps between them and stay there. A single accountable team removes the most common reason growth work stalls.
Look for a partner that says no
Willingness to decline work, recommend a cheaper approach or point you elsewhere is the clearest available signal about how a partner will behave once the contract is signed.
Judge on the second year
Almost any agency performs in the first quarter. The question is whether the relationship still produces compounding results in the second year, which depends on whether they built you something durable or something that needs them permanently.