The Testing Methodology
I tested 10 AI email tools over 50 hours across 3 use cases: writing marketing emails from scratch, improving existing email copy, and optimizing send times. Each tool was scored on speed (time saved vs manual writing), quality (did it require significant editing?), personalization (variable field support), and cost (monthly fee vs ROI).
The Scoreboard: All 10 Tools Ranked
| Tool | Speed Score | Quality Score | Cost/mo | Verdict |
|---|---|---|---|---|
| ChatGPT-4o (with prompts) | 9/10 | 8/10 | $20 | Excellent - best overall |
| Seventh Sense (send time AI) | 10/10 | N/A | $64 | Excellent - different category |
| Phrasee | 8/10 | 9/10 | $Custom | Excellent - enterprise only |
| GrammarlyGO | 7/10 | 7/10 | $30 | Good - editing focus |
| Lavender (cold email) | 8/10 | 7/10 | $29 | Good - cold email only |
| Jasper | 6/10 | 6/10 | $49 | Average - generic output |
| Copy.ai | 6/10 | 5/10 | $49 | Below average |
| Gmelius AI | 5/10 | 6/10 | $15 | Below average - Gmail only |
| Writesonic | 5/10 | 5/10 | $19 | Below average |
| Postaga | 4/10 | 4/10 | $99 | Avoid |
The 3 AI Tools Worth Using
1. ChatGPT-4o with Custom Email Prompts
Not an email-specific tool, but the most flexible and highest quality output when given proper prompts. Key: create a saved prompt that includes your brand voice, target audience, email length guidelines, and CTA format. With a good template prompt, ChatGPT generates ready-to-send emails 70% faster than writing from scratch - and they require minimal editing.
2. Seventh Sense (Send Time Optimization)
This is not a writing tool - it is a send time AI that analyzes individual subscriber engagement history to determine the optimal delivery time for each recipient. In testing, Seventh Sense improved open rates by 23% vs fixed send times with no change to email content. This is the category of AI that actually moves the deliverability needle.
3. Phrasee (Subject Line Generation)
Enterprise-only but genuinely impressive. Phrasee trains on your specific brand voice and generates subject line variants optimized for your audience segment. In head-to-head tests against human-written subject lines, Phrasee variants won 64% of A/B tests on large e-commerce lists.
💡The surprising insight: AI for email writing improves efficiency by 30-50%. AI for email deliverability (send time, subject line optimization, bounce prediction) improves revenue by 20-60%. Deliverability AI has 3-4x the ROI of writing AI.
How LoomiMail Fits Into an AI Email Stack
Use ChatGPT to write your campaigns. Use Seventh Sense or LoomiMail analytics to optimize send times. Then send through LoomiMail for AWS SES delivery at $0.11 per 1,000 emails - 12x cheaper than sending through Mailchimp's AI-enhanced platform for the same result.
Send AI-written campaigns through LoomiMail for $11 per 100K emails
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