I have purchased multiple different email validation/verification tools in the past.

Usually, they charge a LOT of money. If you have a list of 75,000 subscribers, then it can often cost more than $300 a month to maintain it. Other providers charge a high monthly fee.

xEmailVerify is quite strict, and I appreciate that. My emails are checked quickly, and the package deals here are INCREDIBLY affordable.

AAA+++ seriously recommended :)