The ease of use! It is so easy to create an event or send out announcements with this software that I can't think why anyone would dislike it as much they do their current system (which was not designed for social media).
There are many different ways you could have your notifications sent but we chose email/text because our clients like knowing when something happens immediately instead waiting until next day's newsletter which doesn;t always work well depending upon time zones etc.. We also love how fast emails from other users get through versus paper mail where sometimes weeks go by before someone responds even though there has been no delay at sending them via e-mail vs snail mailed letters!!