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Microsoft 365 is the suite everyone compares everything else to, and most coverage gets lost in Outlook and Teams meetings. This article deliberately does not. We are looking at Microsoft 365 purely as a document and collaboration platform, Word, Excel, PowerPoint, the storage and sharing underneath them, and the newer collaborative surfaces, because that is the part the sovereign alternatives in this series are actually trying to replace. Email is a separate fight.
Treated that way, Microsoft 365 is the benchmark, and an honest one. It is the most capable and most integrated document suite available, and it is sticky for good reasons. It also carries a sovereignty cost that has moved from theoretical to board-level. Both things are true, and a fair assessment holds them together.
Short verdict:
- Microsoft 365 is the most capable, most integrated document and collaboration suite, and the benchmark every alternative is measured against.
- Its stickiness comes from the fabric: Word, Excel, and PowerPoint woven into OneDrive, SharePoint, Teams, and Loop, all co-authored in real time.
- The cost is sovereignty: as a US provider, Microsoft carries Cloud Act exposure that data-residency controls reduce but do not remove.
The document core
Set email aside and the heart of Microsoft 365 is the trio everyone knows: Word, Excel, and PowerPoint. What makes them the benchmark is not any single feature but their combination of depth and ubiquity. Excel in particular remains the most capable spreadsheet in wide use, and the desktop applications still do things the web-only suites cannot.
Crucially, these now exist in both desktop and genuinely capable web versions, with real-time co-authoring in both. Multiple people edit the same document simultaneously, with version history and comments, which closed the one gap where Google once clearly led. For an organization whose work lives in complex, heavily formatted Office documents exchanged with the outside world, this is the suite those files were designed for, and fidelity is never in question because it is the reference implementation.
That depth is exactly why migrations off Microsoft 365 are hard. The alternatives can match the common cases, but the long tail of advanced Excel and intricate PowerPoint is where Microsoft’s incumbency bites.
The collaboration fabric
The document apps are not really the lock-in. The fabric around them is.
Microsoft 365 ties the editors to OneDrive for personal storage and SharePoint for team document libraries, then layers Teams on top as the place where documents are shared, discussed, and co-edited without leaving the chat. The newer Loop adds a collaborative canvas and portable components that stay live-synced across Word, Teams, and other surfaces, so a table or task list embedded in one place updates everywhere. Source: Microsoft Loop overview.
The effect is that documents, storage, chat, meetings, and collaborative components are one connected system rather than separate tools. That integration is genuinely productive, and it is also the deepest source of lock-in in the entire office-suite market, because leaving means unpicking not just files but the whole fabric they live in. When you evaluate a sovereign alternative, this fabric, not the word processor, is what you are really trying to replace.
Market reality
It is worth being clear-eyed about scale, because it shapes the decision. Microsoft 365 is the dominant productivity suite, with analyst estimates putting it near half the overall market and a clear majority of the enterprise segment, on the order of hundreds of millions of paid seats. Source: Microsoft 365 statistics.
That dominance has a practical consequence beyond bragging rights: the rest of the world assumes it. Your clients send .docx, your partners share Excel models, your job applicants list Office skills. Any alternative has to interoperate with that reality, which is why Microsoft-format fidelity keeps coming up as a selection criterion even for teams that never open a Microsoft product themselves. The incumbent’s gravity is felt even by the people trying to escape it.
The sovereignty problem
Here is where the benchmark meets the theme of this series. Microsoft is a US-headquartered company, and under the US Cloud Act it can be compelled to produce data regardless of where that data is physically stored. That is the core concern, and it is not solved by choosing an EU data centre.
Microsoft has responded with the EU Data Boundary and an expanding set of sovereignty controls, keeping more processing, now including AI features, within European regions. Source: Microsoft EU Data Boundary. These genuinely reduce data-residency risk. What they do not do is remove the extraterritorial reach that comes from Microsoft’s home jurisdiction, a gap independent analysts continue to flag through 2026. Source: KuppingerCole on Microsoft’s sovereign cloud.
So the honest framing is that Microsoft 365 offers strong residency controls and real security, but not the clean answer to “could a non-EU government compel access to this data” that a European or self-hosted suite can give. Add the proprietary formats and ecosystem gravity, and you have both the highest capability and the highest switching cost in the market. For many organizations that trade is acceptable. For sovereignty-driven ones, it is precisely the trade they are trying to escape.
What leaving actually costs
Because the integration is the lock-in, it helps to be honest about what a migration off Microsoft 365 really involves, since underestimating it is how sovereignty projects stall. The documents themselves are the easy part: most content moves, and the alternatives read and write Office formats well enough for the common cases. The hard part is everything woven around the documents.
You are not just moving files, you are unpicking SharePoint sites, permission structures, shared mailboxes’ calendar links, Teams channels with documents embedded, Loop components living inside other apps, and the muscle memory of an entire workforce. Power users have macros, templates, and intricate spreadsheets that may not survive intact. Identity and device management are often tied to the same Microsoft ecosystem. None of this is insurmountable, but it is a programme of work, not a weekend, and pretending otherwise is how migrations lose credibility halfway through.
The realistic path for most organizations is staged rather than wholesale: move the collaborative, lower-complexity work to a sovereign suite first, leave the genuinely Office-dependent workflows on Microsoft until alternatives or rewrites catch up, and accept a period of running both. That is less satisfying than a clean break, but it is honest, and it is how the public bodies actually migrating are doing it. The lesson is to weigh the sovereignty benefit against a real, sequenced cost, and to budget for the fabric, not just the files.
Who should stay, and who should look
Microsoft 365 is the right call when capability and compatibility outweigh sovereignty. If your organization lives in advanced Excel, exchanges complex documents with a Microsoft-using world, and has no regulatory or political mandate pushing it off US providers, the suite is excellent and switching would cost more than it returns. Staying is a defensible, often correct decision.
You should look hard at alternatives when sovereignty is a genuine requirement rather than a preference: a public body, a regulated industry, or any organization that has to answer the extraterritorial-access question cleanly. In those cases the Cloud Act exposure is not a footnote, and the European and open-source options in this series, from La Suite numérique to a Swiss host like Infomaniak kSuite, exist precisely to give you a different answer.
Final verdict
Treated as a document and collaboration platform rather than an email system, Microsoft 365 is the benchmark for honest reasons. The Word, Excel, and PowerPoint core is the most capable in the market, and the fabric of OneDrive, SharePoint, Teams, and Loop makes it a deeply integrated, productive, and sticky system. As a measuring stick for everything else in this series, it sets a high bar.
The catch is the one this whole series circles: that capability comes from a US provider, with Cloud Act exposure that residency controls soften but cannot erase, and with lock-in that raises the cost of ever leaving. If sovereignty is not your constraint, Microsoft 365 is excellent and you should keep it. If it is, the suite’s strengths are exactly why leaving is hard and exactly why the alternatives are worth the effort. See our hub on sovereign office suites for the full set of options.
