Quick Verdict
Superhuman remains the benchmark for raw speed and keyboard-first power users — and its 2025 AI rewrite feature (draft replies in your voice) is the best in the category. But at $30/month, it's pricey. Shortwave is the best value: Gemini-powered AI triage, bundled summaries, and natural-language search on top of Gmail for a fraction of the cost. Spark is the pick if you juggle multiple email providers and want a clean multi-account inbox.
Ranked List
- Superhuman — Fastest. AI drafts in your voice. $30/mo.
- Shortwave — Best value. Gemini-powered, Gmail-native. $9/mo.
- Spark Mail — Best multi-account client. Readdle-made, cross-platform. $8/mo.
- Gmail + Gemini — Free with Google Workspace. Good enough for most.
- Notion AI for Gmail — If you already live in Notion, the cross-surface search is useful.
How We Tested
Each client was installed on a 3,000-message inbox and used exclusively for 14 days. We measured time-to-inbox-zero, accuracy of AI-drafted replies (rated blind by the inbox owner), quality of AI-generated summaries for long threads, multi-account friction, and pricing at solo and small-team scales.
What AI Actually Helps With
After 14 days per client, the AI features that materially saved time were: (1) auto-triage that learned which senders mattered, (2) thread summarization for long multi-party threads (Shortwave was best), (3) draft-in-your-voice replies for repetitive correspondence (Superhuman was best), and (4) natural-language search ("find the contract Anna sent last month").
The AI features that sounded cool but didn't save time: auto-categorization into folders we never reviewed, sentiment analysis, "meeting invitation detection," and automated follow-up reminders (we mostly ignored them).
Pricing Snapshot
| Tool | Platform | Price | Best For |
|---|---|---|---|
| Superhuman | Gmail, Outlook | $30/mo | Power users, keyboard-first |
| Shortwave | Gmail only | $9/mo | Most Gmail users |
| Spark | All major providers | $8/mo | Multi-account users |
| Gmail + Gemini | Gmail | Free* | Casual use |
*Included with Google Workspace Business Standard and above.