The part I like best about Protected Trust is the ability to set the authentication for each recipient individually using a password or other means. I like being able to control how people end up accessing my emails.
I also like the recent recipients feature since my address book is obviously not in Protected Trust.
I also like that you can send a secure copy to yourself. Review collected by and hosted on G2.com.
I do not like that the messages go away after a certain amount of time. I would like a full history of all the emails I have received and sent to be there when I check 3 months later. Review collected by and hosted on G2.com.