I understand why people are reluctant to trust a single corporation with so much control over their personal information, particularly when, as they say, the user is as much the product as the customer. I'm generally a big defender of Google but even I am disquieted by their maneuvering around Google+.
However, I also doubt it's possible to build services as sophisticated as GMail on direct payments from users. I strongly suspect that very few people would be willing to pay what it would cost to build and run a service like GMail without ads.
I tried Fastmail last year and maybe my impressions are out of date but it can't compete on features at all. The web interface is stone age compared to gmail, search is far slower and less sophisticated, spam filtering was not as good etc. No native apps are available for mobile.
Fastmail isn't bad but I don't consider them to be in the same league.
However, I also doubt it's possible to build services as sophisticated as GMail on direct payments from users. I strongly suspect that very few people would be willing to pay what it would cost to build and run a service like GMail without ads.