The ease in which certificates can be issued to multiple users with different user roles (e.g., Salesforce Admin / Non-Admin). I like that it's easy for our customers who use Trustzone as their CA partner because they don't have to go through an additional process when adding new endpoints or services outside of what we provide them already via API calls from within SFDC itself - this makes life easier! Our clients are happy too since there isn't any need to manage another 3rd party cert authority anymore :) We've been using TrustedZone Certificates successfully now over 2 years without issue; however if you're looking at other providers out there then make sure your requirements match exactly before choosing one vs others so no surprises later down the line!