Excellent at correctness and clarity across everything you type. Its tone detector is a read-out — “this may sound harsh” — and leaves the rewrite to you.
Starts a step earlier: drafts the whole email from one line of intent and the live thread, in a voice you chose, on eight dials you can see. You set the target; it writes to it.
Grammar rarely loses a deal or a candidate. Tone does. Many people keep a grammar checker for documents and PersonaDraft for the replies that carry risk.
This is the core difference. Grammarly’s tone detector is a read-out — a label that says “this sounds confident” or “this might come across as concerned.” It leaves the rewrite to you. PersonaDraft treats tone as something you control directly: pick a voice, turn eight dials, and the whole email is written to match. You are not nudged toward a fix; you set the target and it writes to it.