If your deck has to be a PowerPoint file because that is what your organisation runs on, the AI built into PowerPoint is the path of least resistance. Copilot drafts a deck from a prompt or, more usefully, from a document you already have, applies your company template, and will summarise or reorganise an existing deck. Nothing leaves the Microsoft tenancy, which is often what actually decides this for a large employer.
The output is more workmanlike than inspired, and at around thirty dollars a seat it is the most expensive option here by some distance, which only makes sense as part of a wider Microsoft 365 rollout. Judged as a presentation tool alone it is beaten by Gamma; judged as the one that fits the company you work for, it frequently wins.