When comparing eM Client vs Opera Mail, the Slant community recommends eM Client for most people. In the question“What are the best e-mail clients for Windows?” eM Client is ranked 11th while Opera Mail is ranked 13th. The most important reason people chose eM Client is:
Such as sorting through categories, etc.
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro Many useful options
Such as sorting through categories, etc.
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 Still actively developed
They've been developing and improving it consistently for years.
Pro Calendar inclusive
Pro Beautiful interface, customisable to your needs
Pro It's simple to add new accounts
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 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 The only email client which synchronizes Gmail contacts properly
Pro Doesn't replace your attachments with "winmail.dat" files
eM Client sends straight .pdf files for fax messages flawlessly.
Pro It doesn't store all emails on the disc
It saves space, unlike Thunderbird.
Pro It is still the best in this class
But only because it has no alternative.
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 Very fast
Pro Intuitive user interface
The design of the UI in Opera Mail is clean and intuitive, making for an easy to use client.
Pro Very efficient search
Be it the subject or the sender, it is very fast and accurate.
Pro Opera Mail CAN BE set as default email client in Windows 8 & 10
Pro Automagic smart filtering
After a bit of use Opera learns what e-mail belongs in what folder just by previous usage. This makes for a convenient way to have e-mails filtered without having to manually mange every e-mail.
Pro Free and based on Mozilla code
Opera Mail is completely free to download and use and it is based on Mozilla's code, which is what makes it a bit similar to Thunderbird in looks and function.
Cons
Con Extremely slow opening emails
Con Some syncing errors with Hotmail
Happens from time to time.
Con Bloated
Huge size, high memory consumption, uses CEF (Chromium Embedded Framework).
Con Lifetime Upgrades are expensive
Con Account options are not shown under right click
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 Not many options to manage IMAP folders
For example, all emails from Gmail will unnecessary synchronize.
Con Interface is too simple
Many options are too hidden and it takes at least 3 clicks to set them up.
Con No conditional formatting
Con Only has one nice interface/skin
The other available skins has a 90s feel to them.
Con Being discontinued
Opera Mail will be end of lifed per Opera website
Con Very limited feature set
Compared to Thunderbird.
Con Sync is slow
Opera tends to be slower on e-mail sync when compared to other popular clients.