I am so happy with its Import Data feature. It can import data from your Email Marketing Sites. You don't need to filter your data from this site and then upload to your Email Marketing Sites. It can directly access your Email Marketing accounts and filter your data.

It is a good source to verify the email address to avoid bounce rate.

It is a very simple/intuitive app to use. Each email that we send costs me money; consequently, we do not want to waste money sending emails to non-existent or bad addresses..