We used a few different email verification apps, like mailjet and leadrocks.
When we used leadrocks to clean, we ran into issues with high bounce rates. Mailjet charged us per email, and it ended up costing $30+ per cleaned list. Ive tested reoon on 10 campaigns now, and we have had little to no hard bounces and a much lower soft bounce rate compared to leadrocks and a few other apps. We are really happy with it. Especially the speed. The ability to download the different list segments instead of sorting through the list ourselves has been a big help. 5 Tacos