I like that it's easy for me as an admin user with limited tech knowledge (I'm not sure if this was intentional or what) but my main issue here would be how much time does take before you get results back from them after submitting data? The turnaround times are sometimes too long so we have had issues getting our mailer lists cleaned up quickly enough when sending out newsletters/emails etc at short notice - which can lead us into problems! We've been using Captivator since 2016 now though they do seem quite responsive in general once submitted information has gone through their system properly :) If there were some way where people could see exactly why certain email address' weren't being verified correctly then maybe more users will use these services than otherwise might think about doing something themselves?! It helps keep all contact details accurate within one place instead having multiple.