I got to know about this site from my friends.when I was not too much familiar with the Internet.But when I came to about all such sites I followed only gmail because of its privacy concern.If u r a professional and want all kind of privacy for your mails.Gmail will provide you the platform.If u will face some problems it will also provide the proper solution of it.
At last I will say it protect your right to privacy better than other sites .just no worry and go for it.