When comparing Mozilla Thunderbird vs Spark, the Slant community recommends Mozilla Thunderbird for most people. In the question“What are the best e-mail clients for macOS?” Mozilla Thunderbird is ranked 3rd while Spark is ranked 5th.
Ranked in these QuestionsQuestion Ranking
Pro Free (as in freedom and beer)
Pro Lightning Calendar and Address Book integration
Pro Good filtering system
Mozilla Thunderbird offers a flexible filtering system with the ability to set flags and read/unread, as well as sort/assign to new mail directories. There are also numerous plugins available to assist in the filtering.
Pro Consistent and involving a moderate learning curve
The app design of Mozilla Thunderbird has not changed significantly since its beginning, making its learning curve almost non-existent.
Pro Available on Linux, OS X and Windows
Pro Large assortment of plugins available
Mozilla Thunderbird offers a huge amount of extensions to expand the usability and options of the client.
Pro Very reliable
Version after version, Mozilla Thunderbird works as expected.
Pro Tabs for navigation
Pro Send large files easy
Install pCloud plugin for Thunderbird and your files (upto 20 GB free storage included) will be received as download links
Pro Custom quick swipe features
Pro Free snooze options
Pro Robust customization options
Con Terrible integration with macOS
Simple things - drag/dropping pictures doesn't work, for instance.
Con Development slowed to only focus on stability and security
Mozilla Thunderbird has slowed down its development of features to only focus resources on security and stability.
Con Subject lines can (temporarily) disappear from the list
This is sporadic behavior.
Con Serious bugs
Clicking on a subject line can bring up the wrong email.
Con Outdated interface
Thunderbird's interface is very outdated and unpleasant. It feels more like a Windows XP application than like a modern MacOS one.
- Sends statistical data to several services known for bad privacy policies (Google, Facebook), also there's no way to opt out.
- Automatically creates an acount with the first address entered and subscribes you to their newsletter.
- Stores credentials for your email accounts on their servers.
- Stores your emails on their servers to push them to your devices.
- Server infrastructure seems to be located in the US.
Con Doesn't show the counts of emails next to the folders
- On the Mac platform will show +999 for the folder that contains more than 1000 emails.
- On the iPhone, the platform will not show the counts next to the folder unless they are new emails.
Con Doesn't support many services
Many services such as Spam filters, Pocket, and other apps are not supported.