Compare approaches
Agency or independent specialist?
The useful comparison is the actual delivery arrangement, including dependencies and review.
Independent specialist
Confirm their specific scope, availability and any tasks requiring other people. A smaller engagement still needs source ownership and a recovery plan.
Agency team
Ask who is accountable day to day, which roles are included and whether work is subcontracted. Team size does not by itself establish quality or continuity.
The decision to resolve
Can you identify the people, deliverables, boundaries and handover for this particular proposal?
Compare proposals fairly
Use the same deliverables, responsibilities, access assumptions and acceptance evidence for both options. Confirm actual availability and terms with the responsible provider.