Best all-rounder — the safest choice if you only pay for one assistant
ChatGPT is the broadest assistant available and the sensible default for anyone buying exactly one. Its advantage is not any single capability but the absence of gaps: web search, file analysis, images, voice, code execution and custom agents all work well enough that you rarely need a second tool.
Best for companies already running Google Workspace
Gemini is the obvious answer for Google Workspace companies: it reads your Drive, Gmail and Docs natively with no integration work. As a standalone assistant it is competitive rather than leading, and its consumer plan bundling can be confusing.
Best for research where every claim needs a checkable source
Perplexity is a research tool rather than a general assistant. It searches the live web and cites inline, which makes it the most verifiable option here — and the least suited to open-ended creative or coding work.