I just used Brandnav Verifier and Shield. Here is my review:

First, let's understand our background:

We are a lead generation agency working with several clients and sending around half a million emails per month. Each month, we verify over 100K lead lists and use several LTDs like MailRefine, Kleanmail, and Truemail, as well as paid tools like ZeroBounce and Bouncify. So, the email verification tool is a part of our process and we are aware of most tools in the market.

The problem with most tools is that they return many emails as invalid or unknown. Since we double-verify leads, we have seen almost every single time that 35–45% of those are valid but tagged invalid or unknown by tools. I am not a tech expert, but this might be because of delays or any other reason.

On BrandNav, we found that their results are faster and more accurate, with very few invalid or unknown contacts.

This is very important for clients with a low TAM, and every single email is important. Also, there are people who send emails to valid and catch all emails due to various reasons.

I am not a big fan of LTDs and have never gotten any deals recently, but this is worth a try. Check it against the best tools and stack max while you can.

Brandnav Sheild:

For this, I think the team should work on a demo of how to use it or make it simple. Being so into technology, I wasn't able to use it. If anyone from the team can share more about this one, I'd be happy.