For a study, researchers sought to determine the benefits and drawbacks of using the (SW-CRT) Stepped-Wedge Cluster design for large-scale intervention implementations in primary care settings. The Agency for Healthcare Research and Quality’s EvidenceNOW: Advancing Heart Health initiative contained a huge collection of SW-CRTs. Investigators interviewed 17 key informants from EvidenceNOW grantees to determine the benefits and drawbacks of employing the SW-CRT design. According to all interviewees, SW-CRT can be a successful study design for large-scale intervention deployments. Incentivized recruiting, staggered resource allocation, and statistical power were all benefits. Among the challenges were time-sensitive recruiting, retention, randomization needs and practice preferences, treatment schedule fidelity, rigorous data collecting, the Hawthorne effect, and temporal patterns. EvidenceNOW grantees’ problems suggested that some advantageous real-world conditions created an environment that boosts the chances of a successful SW-CRT. Many can be recruited using existing infrastructure. Strong retention plans were required to keep sites engaged while waiting for the intervention to begin. Finally, study outcomes should be those that were already recorded in ordinary practice; otherwise, funders and investigators should consider the feasibility and cost of data collecting.