Copilot Cowork's architecture is surprisingly well-balanced. The frontend UX is unusually smooth and responsive for a Microsoft product - none of that typical enterprise bloat. But underneath, it's tightly integrated with the M365 stack. This hybrid approach actually works: modern UI/UX layer on top of Microsoft's enterprise infrastructure. The performance feels more like a native app than a typical M365 web experience, which suggests they've done serious optimization work on the rendering pipeline and API calls. Worth checking out if you're already in the M365 ecosystem and want something that doesn't feel like legacy enterprise software.