Email list "cleaning" is a very good practice that helps you to improve your email delivery rates and sender reputation. We highly recommend our customers to use 3rd party software to check their lists and to remove any invalid mail addresses prior to any mailouts. While you can try to clean your mailing list manually by deleting invalid format email addresses, previously bounced email addresses etc., professional services do this job better. Email List Cleaning is a service we recommend that other customerssome of SMTPour customers have used and said was very effective.
Relative to the service you mentioned, I'm not familiar with it, but you can try how it works and tell us the results.