Great way of checking an email address is correct, and how many times it has been used before. I can check all emails that have been sent out in previous months. Very helpful for when you are adding new members to your database. Only downside is that it takes some time to load sometimes. If you are using it as part of a mailing list, then this is perfect! It saves me time by ensuring there are no mistakes with our mailing list. I like the ease of use. It's a simple, effective, and cheap solution that works for most. I like that it doesn't require any prior coding experience. I dislike that it doesn't have an API or a mobile app. I also dislike that it doesn't work with other email services. I use it to validate my email lists. I can quickly get results and have them in a spreadsheet in less than 30 seconds. I'm able to quickly find out if an email address is valid or not. It's cheap, and I get results quickly.