The case for adopting Gmail is compelling if not over-whelming:
When many big players are trying to lock you in permanently to their "ecosystem", Google merely want to entice you to increase your use of the web and their search engine. They offer an extraordinary 15 GB of free storage. It comes with almost no strings attached ... Except that you become more dependant on Google and maybe give up a little bit more of your independence. But in this brave new capitalist world, nothing in life is free ...
The service can be configured to use other email addresses, so if you want to keep your old primary email address and bunch of other secondary email addresses you can. And you get to read them from one central point.
You no longer have to setup your MUA for each computer you use. All you need is a browser. If it is Safari running on an old Mac Pro, An ancient XP machine running Firefox behind a corporate firewall, a Windows 7 machine running Chrome, a modern high performance workstation running Firefox on Ubuntu 14.04, an ancient PC with a dodgy graphics card running Kubuntu 14.04, an Android Tablet or a flaky old Samsung Galaxy smart phone ... Or in your humble blogger's case ... All of the above, all you have to do is point your browser at Gmail, and provided it's not blocked by the proxy, you get a similar "user experience" on all platforms ... An interface that is well designed and flexible and capable of doing most of things that you might want an MUA to do.
It integrates seamlessly with Gmail contacts, Google Calendar, Google Drive, Google Docs and if you're into that sort of thing, Google Plus. You can store your stuff in the cloud and not have to worry so much about backups. You can share your documents and work on them collaboratively.
And the recent improvements to Gmail categories means that Google will sort all your email into Inbox (personal stuff that you really want to see), Social (stuff that might be interesting but you maybe don't want to see right now), Promotions (stuff that you might want to see but only rarely) and Spam (stuff that you probably never want to see). And Google's categorisation algorithm is without doubt the best in the world. Sure, they troll through your email, in order to categorise it ... And that might worry some folks who are concerned about privacy ... But Google bring to the categorisation task all of their formidable search technology and the results are truly impressive. Better even then the amazingly efficient Spam Assassin ... Google gets it right about 99.9% of the time ... And if you report the 0.1% that you disagree with to the categorisation management algorithm, Google will get it right 99.999% of the time ... Which is good enough for your humble blogger.
It's portable. Provided you observe a few common sense guidelines about security, you can sit down at a foreign computer, startup a session and point the browser to Gmail and read your email ... Maybe you have to do this because your portable phone just went for a swim in the duck pond ... Or the battery suddenly decided to stop working ... Or just because you want to ...
Yes, Google is your new homepage ... And your new inbox ... And your new Calendar ... Your new black book ... And your new memory stick.