I like that it is so easy to use, you can create your own templates for different scenarios with ease! Also very customizable (you have many options).The fact that there's no limit in terms of number of files or size allowed makes things easier as well.
The only thing i dislike sometimes are some minor inconveniences such as having an option to automatically download all attachments from emails without me needing to do anything special about them. Other than that everything works fine! It has been great using this software because it allows us to keep our customer data safe at any time by encrypting their documents before we send out to them via email.