I am deeply rooted in Microsoft Office.
I am a senior physician at a big university clinic and I am totally dependent on Microsoft Office.
I do most of my day to day work in Microsoft Office, I write research papers in Word, my doctoral students do a lot of their work in Word and Excel, which I have to be compatible with, I prepare talks and lectures in PowerPoint and so on. For me these are easiest to work with and I am also pretty content with the 2016 versions of said programs.
They work really well for me on my Macs and iOS devices and I can get them for free as long as I am working and teaching at the university, which is another plus. And they are compatible with Papers 3 for Mac, my research library management software (which I also use to create references in research papers).
Honestly speaking, I never really warmed up with the iLife suite.
The only application I don't use is Outlook, which I consider quite horrible.