Another happy customer of Fastmail here, and these are my opinions why you should give it a try:

1. They often express their opinions on topics like security and privacy. Like how things impact their users, where they stand, and how they plan to do. As a user I am happy to see a company actively talk about hard topics like these.

2. While they are not the most stable software service I ever use, but they always provide timely update. They also write postmortem to explain what happened technically, what did they do, and their future plans. As a developer, I am appreciated when a software company spent extra effort to acknowledge and explain issues of their service.

3. Their business model is simple. I pay money, they provide service.