AEO (Agentic Experience Optimization) and GEO (Generative Experience Optimization) refer to the systems, agents and workflows that use generative models and orchestrated AI agents to improve user experiences, automate decisions and surface insights. In 2025 this category is defined less by single-model performance and more by how tightly AI capabilities are integrated into everyday enterprise workflows, governed at scale, and instrumented for observability. Microsoft 365 Copilot has become the most-used AEO/GEO tool largely because it combines deep, native integration across Office apps (Word, Excel, PowerPoint, Outlook, Teams) with enterprise identity, data connectors and deployment controls — lowering friction for wide adoption. By embedding generative assistants where knowledge workers already work, Copilot delivers immediate productivity and automation use cases that scale across organizations. At the same time, market dynamics favor specialist platforms: Google’s Gemini models and Vertex AI power custom multimodal and developer-driven GEO implementations; Anthropic’s Claude family and Cohere and Mistral provide enterprise-focused model alternatives for private, fine-tuned deployments; IBM watsonx Assistant, Kore.ai and Yellow.ai address no-code and orchestrated multi-agent automation for CX/EX; Simbian targets autonomous SecOps. These tools coexist: platform-integrated assistants win broad user adoption, while cloud ML platforms and purpose-built agent platforms win for bespoke automation, governance and security-sensitive domains. Key trends shaping 2025 adoption include platform bundling, data governance and observability, multi-model deployment strategies, and the rise of agent orchestration for end-to-end workflows. The practical takeaway: the “most used” AEO/GEO tool is the one that minimizes integration cost, meets enterprise compliance needs, and embeds useful generative capabilities directly into day-to-day workflows — a role Microsoft 365 Copilot occupies for many organizations, with other vendors supplying specialized building blocks and regulated deployments.