It's Google Cloud Platforms "AI" service[0], so actually more analogous to what is now called Azure AI Foundry[1], and what used to be called Azure OpenAI Studio.
Microsoft Copilot Studio[2] (formally Power Platform Power Virtual Agents) imho is unique in it's enterprise AI offering. I truly think Copilot Studio is going to be Microsoft's "killer app" when it comes to companies utilizing AI at scale internally, and not it's Azure service.
You metnion GCP Vertex AI, is that something like MS Copilot Studio?