Paul Turley makes a recommendation:
Pilot versus enterprise-wide is the wrong debate. The real question is which one your organization is actually ready for.
Start narrow, then earn scale.
Microsoft’s capacity planning guidance recommends beginning with a proof-of-concept phase on a free 60-day trial capacity, a single use case, a small user group, and an isolated workspace so nothing touches production. You’re testing the concept, not committing the whole company. That isolation matters as much as the scope — keeping the proof-of-concept out of production workspaces means a bad assumption costs you a workspace, not a week of executive reporting.
Read on for a few more tips along these lines.