Rackspace Mail: $24 (159rmb) per user*

Rackspace is one of the more popular Gmail alternatives — the English-language service has a generally good reputation for being reliable, effective and well-priced for the features offered. It's suitable for businesses: up to 100GB email mailboxes (Hosted Exchange) and up to 25GB (Rackspace Mail end users).

Mailboxes use Microsoft Outlook, though only Rackspace's Hosted Exchange has the full range of compatibility and synchronization across desktop, web, and mobile devices, plus sharing and connecting users through public folders, calendars, contacts, and task lists. This premium option runs at 120 dollars a year per mailbox, or 795rmb.

There's also an option to add "Email Archiving" for an additional 36 dollars (that's 239rmb) per mailbox, per year. This feature does an auto backup for every piece of email whether incoming or outgoing, allowing you to immediately locate any email from past or present. Note that this add-on will have to apply to all mailboxes in your company domain, so you can't pick and choose which users get it. 

There's a 14-day free trial to start with, and new users get tutorials to help with the transition, plus direct support from Rackspace staffers to get familiar with the service. Rackspace can do attachments up to 50MB and all clients receive 250MB of SharePoint storage for each email account registered.

Here are some additional points from Spiceworks user reviews to consider:

"Tasks like renaming, migrations, resynchronizing, and application upgrades are apparently really tough for them... The simple things like autodiscover in Outlook work quickly, and the mailbox sizes have become pretty generous for this price point. The documentation (though cluttered with older versions) is thorough and easy to follow. Lighting up new accounts is quick and easy to do. The layout of their UI makes sense and has a very quick learning curve."  —WPAdmin

"The ability to add accounts in a mixed environment is nice too, I use Exchange for my own email while giving my son a standard email account on my domain for an extra $2 (13rmb/month) since he doesn't need the advanced features."  —msteinhilber

Office 365: $60 (375rmb) per user and up*

Microsoft Office 365's basic cloud email service includes storage and sharing of up to 1TB per user and 50GB inbox space for email messages, calendars and contact lists. There's an option to upgrade to the "Office 365 Business Premium" for 150 dollars, or (995rmb) a year, which tacks on the full package of Microsoft Office programs such as Word, Excel, PowerPoint, OneNote and Outlook for PC, Mac, tablets, and phones. 

For either option, users can download the online versions of Office programs to many devices (desktops and mobile devices) without having to bother with disk installation, plus access to Office web apps. Built-in tools for video conferencing, sharing calendars, task lists and schedules are straightforward and run smoothly. If consistent internet connectivity is not your friend, then take note — many users have reported outages on the online service and its functions even with stable internet connections. However, reviews on the overall experience of using Office 365 for email are generally positive up until this point.

Beta News has a really nice, comprehensive review of the experience of using Microsoft 365. It's largely positive: "A first-rate, non-discriminating browser-based experience. The old Office 365 webmail interface, via Outlook Web Access, was marred by the 'best viewed in Internet Explorer' dilemma. No such thing in the newest release. Even Chrome and Firefox can enjoy the niceties of this refresh... Spam & malware filtering on par with Google's Postini engine... False positives are nearly non-existent, and inboxes are finally kept squeaky clean."

Aliyun Mail: 600rmb+ [shared accounts]*

For those who can navigate the Chinese interwebs, or are patient enough to go through the Google Translate process for registration, then Alibaba's email service Aliyun mail, or AliMail, is certainly worth the effort — especially for those looking to save a bit of dough. It offers a, let's say, strikingly similar look and feel to using Gmail, which should make for a fairly smooth transition. It's iOS and Android compatible, there's a "message recall" feature so that you can un-send recently sent unread messages, all sent messages are automatically saved in the Sent folders across your devices and so on.

Yearly subscriptions start at 600rmb for a basic account (up to five users), 1875rmb (up to 20 users) and 2600rmb (up to 40 users). The prices gets a bit cheaper if you spring for a two year subscription in one go—3000rmb (up to 20 accounts) and 4550rmb (up to 40 accounts), for example. See the full pricing details (only in Chinese) on this page. Note that this page is only available to those who are accessing AliMail from within Mainland China, so if you've got a VPN on, you should turn it off before registering. Attempting to access the page from outside of the Mainland gets you re-directed to an international info page for Aliyun Cloud services, which bypasses the whole AliMail service option.

So all in all, it's easy to use, efficient and reliable — but the real draw is that the service works really fast in China without any need for VPNs. Inbox capacity is 5GB per user, with network storage of 20GB, for the basic package, though that gets upped to 10GB and 50GB, respectively, for more premium options. You can also customize the login and interface with your company logo, designate domain aliases, account aliases, all that good stuff. 

QQ Mail: 750rmb+ [shared accounts]*

This one is from Tencent, and it's China's most popular email provider for personal accounts. Same ideas here for the business accounts—you can register for your own domain name, integrate logo customization, sync-able calendars, to-do lists and contact books, etc. The biggest advantage to using QQ Mail, however, is that your email account can be connected to the Mainland's most inescapable, omnipresent apps, WeChat and QQ. This way, you can get in-app alerts related to your email account and send super quick responses from any device.

Some of you may already be on QQ Mail for personal accounts, which is great for foreigners in the Mainland thanks to its quick, no-VPN access and English interface, though QQ Mail for Business isn't quite there yet with usability in English so you'll still have to be a bit savvy with the Chinese language to navigate the service.

QQ Business Mail also supports large attachments of up to 2GB per message, which is nice (Gmail only does maximum 25MB per email). Costs per year: 750rmb (up to 5 users), 2960rmb (up to 20 users), 7250rmb (up to 50 users) and 14,000rmb (up to 100 users). Inbox space is up to 32GB for each user account, while network storage equals the number of users in each tier (5GB each for 5 users, 20GB each for 20 users, 50GB each for 50 users, etc.)

163 Mail: 1000rmb+ [shared accounts]*

Aside from QQ Mail, 163 from Chinese tech company NetEase is the other major, widely used email provider of choice within the Mainland. While both are immensely popular for individual email users, 163 for Business seems to be slightly more favored amongst Mainland Chinese companies. After initial registration and payment, there's even an option to toggle the interace between English, traditional, or simplified Chinese. You can scope out the English version of their login page here.

On desktops, 163 Mail looks not unlike Hotmail — not the most stylish, but it's straightforward as hell. NetEase has developed nice, simple-to-use apps for 163 Mail too, available for both iPhone and Android. As usual, users can sync their inboxes across desktops and devices, and the service is compatible with Microsoft Outlook and FoxMail. Try the 7-day free trial option in case you want to give it a whirl.

The cheapest basic plan is: 1000rmb a year for up to 5 mailboxes, 5GB of inbox capacity, up to 100MB for each attachment, 1GB of network storage. The upgrade to this basic plan runs for 1500rmb a year and ups those numbers to unlimited inbox capacity and 5GB of network storage. For up to 20 users, the prices goes up to 3700rmb a year, or 5550rmb for the upgrade.