I like that it is free, easy to use (for employees) and cheap compared with other services out there.
It was good for my business needs when we used it at work but now our team uses Gmail accounts so this service isn't as useful anymore! Free temp mail address solution if you're using Google Apps or in need of something quick & simple to set up for your users/employees who don't have their own domain names yet. We needed some sort of way to provide usernames and passwords to new hires quickly without having them create profiles themselves. This solved all those problems very well.