Office used to be $600 for one copy that could run on one operating system.
I can now get an Office 365 subscription for $99 a year for five users and I can use it on my Mac, a Windows PC, iPad, iPhone and all five users get 1TB of storage each
Office is also just cheaper, it's 1/4 the price for the lifetime license than it used to be. The family offering is still the best deal I've seen to get it though. Not all subscriptions allow multiple users or even you to use it at the same time on multiple devices though, Office is just pushing that sale.
Plus the latest version of the software. I would still be using Office 2013 if I had to pay what I paid for it to upgrade every release (multiplied by the half a dozen or so O365 licenses I'm currently using.)
