I have run more than 30 email lists to verify within the last 2 weeks with smtping validation tool. During the last 2 years, I used more than 5 email validation platforms, mainly for B2B lists but also mixed lists. Our sending frequency is 3 times/week (excluding transactional and abandoned cart sent emails).
Validation quality: among the 30 validated lists, we never got a bounce rate higher than 1.2% (and all of them are soft bounces related to common connexion issues). Also, we always doubted that we had a high number of catchall emails on our lists, and smtping's tool confirmed that, around 22% of the emails in our lists come from companies catchall servers.
Performance: we have a range of approximately 10-20k on each validation, the average time is always 10 to 15 minutes, which is excellent
Support: highly responsive, very arranging, and straight to the point.
Overall: we will probably buy some other codes since our needs in email lists are growing, until now, we have never witnessed an offer like this one, both in quality and in quantity.