I like that we are able to identify invalid emails and remove them from our deliverable list. The interface is easy to use and I don't have any complaints about this software at all. The only thing I dislike is that sometimes it can take longer than expected for a message to be removed from the database. This does happen but not very often. If you want to know if your list of valid emails is correct, then this is definitely the solution you need. It helps us filter out invalid emails so we can focus on delivering messages to our customers.