Speed only helps if the agency is shipping learning, not a bloated backlog. The useful agency pattern is a short discovery, one workflow in production, and a handoff you can run without them. If the pitch is months of roadmap with no acceptance criteria, you are buying project hours dressed as an MVP.
Ask who the senior engineer on your account will be, whether you own GitHub and cloud from day one, and what happens when scope changes mid-build. Those three answers separate launch partners from content mills.
Ascendra Ventures focuses on fixed-price atomic MVP and SaaS slices with that ownership model. Worth comparing against any agency timeline you are evaluating.