I spent a brief time years ago pumping the mail from my terrible workplace e-mail server to Gmail, which obliterated many sins (low capacity, terrible software and hardware) while giving rise to others (Google is data-mining us like crazy).
Well, after years of IMAP in Thunderbird, I'm changing course. I'm letting Google's Gmail handle my work mail again.
I'm aware that Google is using my e-mail to craft marketing messages it will aim at me. I don't like it, but I don't hate it enough to suffer through my current mail routine, with the inbox maxing out more days than not. That leads to all sorts of lost productivity on my part.
And my coworkers are making increasing use of Google Drive/Docs, Calendar and Google Plus (with plenty of Google Chat/Talk and Hangouts).
My thinking: If I'm doing all of that, Gmail doesn't add much to the spy vector. And this is for work only. I've been trying to do most of my personal e-mail off of Gmail -- and every other ad-supported e-mail service.
But faced with a poor e-mail system that I must use daily, Gmail makes it much more usable. Google has won me over. Again.