SMTP2GO vs. Customer.io
Side-by-side across both vendors’ full G2 portfolios — reviews, ratings and category coverage aggregated to the company, not a single product.
| Metric | SMTP2GO | Customer.io |
|---|---|---|
| Avg. rating | 4.7 | 4.4 |
| Total reviews | 226 | 990 |
| Review growth (QoQ) | — | +7.1% |
| Products on G2 | 1 | 1 |
| Categories covered | 1 | 7 |
| Best category rank | #24 in Transactional Email | #1 in Transactional Email |
| Small Business | 63.4% | 59.3% |
| Mid-Market | 29.9% | 37.4% |
| Enterprise | 6.7% | 3.2% |