The best feature is that it allows you to send information straight from your mailbox without having to login or navigate through different sites in order to find one of my emails. It's very helpful for when I need to quickly email someone about an issue. Other than that, nothing. There are some bugs here and there but they're usually fixed within 24 hours so not much to worry about. They also have great customer service! If anything ever happens, I'm contacted almost immediately after reporting the problem. Emailing coworkers/supervisors can be difficult because sometimes their inboxes may get full. This helps solve this by sending them messages directly to their mailboxes.