The Microsoft-vs-Google question gets asked on nearly every new engagement. The honest answer depends on what your operation actually does, and the right call is rarely driven by which email client the owner prefers.
01The short version.
Microsoft 365 is the right default for most professional-services operations: law firms, medical practices, finance, accounting, and traditional SMBs with 25+ employees. Google Workspace is the right default for technology-native operations, marketing agencies, some nonprofits, and operations under 25 people where deep Office-app usage is rare.
There are exceptions both ways. This is a starting point, not a rule.
02Where Microsoft 365 wins.
Deep Office document compatibility (real-world Word and Excel usage that Google's versions approximate but don't match). Mature compliance stack for regulated industries (HIPAA, CJIS, legal hold). Identity platform (Entra ID) that integrates with every enterprise IT tool ever built. Security product depth (Defender suite, Purview, Intune) that has no real equivalent in Google.
For a law firm dealing in redlined contracts, for a medical practice needing detailed audit and retention, for an accounting firm running heavy Excel models, Microsoft is the correct answer.
03Where Google Workspace wins.
Real-time collaborative document editing (still better in Google Docs than Microsoft Word Online). Lower operational burden, Google Workspace is genuinely easier to administer for small operations. Lower per-seat cost at the base tier. Gmail interface that many users significantly prefer. Strong mobile-first workflow.
For a 15-person marketing firm, for a tech startup, for operations where everyone collaborates on the same few shared docs all day, Google is often the cleaner fit.
04Compliance and security.
Both platforms support HIPAA BAAs, both can be configured to meet most compliance frameworks. Microsoft has a deeper native toolset for regulated industries; Google can get there but typically needs more third-party add-ons.
For legal e-discovery, Microsoft's Purview stack is meaningfully more mature than Google Vault. For financial compliance, Microsoft's retention and audit tools are typically the better choice.
05Migration reality.
Moving from one to the other is painful but tractable. A 50-person Google-to-M365 migration takes 6–10 weeks and costs $8,000–$20,000 in professional services. Going the other direction is similar.
Don't pick the platform based on inertia alone. If you've outgrown Google's toolset for your actual regulated workload, or you're paying Microsoft for features you never use, a migration is cheaper than you think and the payback arrives within a year.
Google → M365 and M365 → Google, both directions, quoted to the seat. A 40-person Naples professional-services firm typically migrates in 6 weeks for $12,000–$16,000 in services plus licensing. 30 days of post-migration hand-holding included; day-of is staffed, not voicemail.