When comparing eM Client vs Mailspring, the Slant community recommends Mailspring for most people. In the question“What are the best e-mail clients for Windows?” Mailspring is ranked 4th while eM Client is ranked 15th. The most important reason people chose Mailspring is:
The UI is very well designed and neat.
Ranked in these QuestionsQuestion Ranking
Pro Beautiful interface, customisable to your needs
Pro Doesn't replace your attachments with "winmail.dat" files
eM Client sends straight .pdf files for fax messages flawlessly.
Pro Includes Quick Text
eM Client seamlessly integrated the Quick Text extension that was available on Thunderbird. This makes it easy to quickly auto-insert dynamic text, based on many variables, saving time and the need to tediously repeat manual text replies.
Pro Still actively developed
They've been developing and improving it consistently for years.
Pro The only email client which synchronizes Gmail contacts properly
Pro Many useful options
Such as sorting through categories, etc.
Pro It doesn't store all emails on the disc
It saves space, unlike Thunderbird.
Pro It's simple to add new accounts
Pro Free and paid version
It is free for 2 accounts and as long as you don't use it commercially. Paid version comes with support and can handle more than 2 accounts.
Pro Calendar inclusive
Pro Chat included
eM Client includes integrated chat, so you don't need another application for chatting with your friends. All common chat services supported (Google chat, Jabber and others).
Pro A perfect companion to your Gmail or other webmail you might have
It provides (almost) complete Gmail functionality (calendar, tasks, chat, contacts), while offering advantages of an application: offline use, more e-mail providers in one place, very good design, support, etc.
Pro It is still the best in this class
But only because it has no alternative.
Pro Very fast
Pro Neat UI
The UI is very well designed and neat.
Pro Unlimited number of accounts
Pro CPU / battery efficient
Mailspring uses a C++ sync engine designed to be as efficient as possible, so you can leave the app running and not see your laptop battery life drain away.
Pro Snoozing support
You can swipe to archive / snooze messages and specify when you'd like them to resurface in your inbox.
Pro Unified inbox
Using a single inbox for all of your email accounts helps you get more done in less time. Mailspring supports every major mail provider—Gmail, iCloud, Office 365, Outlook.com, Yahoo!, and IMAP/SMTP—so you have a single, streamlined command center for all your messages.
Pro Read receipts and link tracking
Activity tracking is built into Mailspring so you get notified as soon as contacts read your messages and can follow up appropriately.
Pro Great integration with Gmail
Mailspring has great integration with gmail features and tags.
Con Constant syncing errors
Con Not many options to manage IMAP folders
For example, all emails from Gmail will unnecessary synchronize.
Con Account options are not shown under right click
Con Interface is too simple
Many options are too hidden and it takes at least 3 clicks to set them up.
Con Only has one nice interface/skin
The other available skins has a 90s feel to them.
Con Terrrible in handing unread emails
Sorting of unread emails is very useless when compared to other email clients.
Con Poor integration with Yahoo Mail
Integrations with a Yahoo Mail account doesn't always work well in eM Client.
Con Can't use without creating a Mailspring ID
There is no need to create a third party ID for an email client. What if the Mailspring closes in the future - can't install a previously downloaded Mailspring software any more to continue using it or access your stored emails?
Con No portable windows (.zip) bundle available
Con Pro subscription model
To use some features, like contact profiles and link tracking more than a few times a month, you need to pay for a Pro subscription.
Con No addressbook
Con No way to see messages as plain text
And HTML is only optional.
Con Very limited user interface
No way to see the messages as a list, no way to rearrange views.
Con UI is sluggish (Windows)
Click and only after a tiny delay (~half second) something happens.
Con Does not support multi-user installation (Windows)
But instead installs to the user's home directory.
Con Does not support POP