Recs.
Updated
Ad-free business Email Hosting with a clean, minimalist interface. Integrated Calendar, Contacts, Notes, Tasks apps. Free for up to 50 users.
Specs
Pros
Pro Free custom domain name based addresses
The industry concensus is that hosted email services for a custom domain name are worth roughly USD$2 per month per mailbox. Zoho offers you five mailboxes for free and you can attach multiple domain names as well, with one as the primary and the rest as aliases.
Pro DKIM signing
Email is evolving to handle the ever-increasing deluge of spam, and one of the bedrock standards in use is DKIM, a way for your e-mail server to sign every message you send cryptographically with a key that matches one published for your domain. Zoho is currently the only free service that will host custom domain email with the option to use DKIM signatures.
Pro New and different
It provides a different more dedicated services than the more popular alternatives. The integration and functionality is interesting and sounds pretty useful.
Pro An excellent introduction to email server management
You can learn to assign catch-all accounts, spam quarantine policies, migrate messages from other servers, create DKIM and SPF records, and manage user permissions all from the Zoho Control Panel. These skills will all translate well to administering a proper e-mail server of your own, even if they are simplified.
Cons
Con No POP or IMAP for free plan
If you are using free plan you might be locked to their clients.
Recommendations
Comments
Out of Date Pros + Cons
Con The UI and UX have some issues
While Zoho Mail has a lot of potential, it is far from being the ideal email provider. The main problem is that UI/UX looks promising but isn't as amazing as you would expect. It's hugely underwhelming and while robust, pretty rigid.