When comparing Sylpheed vs MailBird, the Slant community recommends Sylpheed for most people. In the question“What are the best e-mail clients for Windows?” Sylpheed is ranked 12th while MailBird is ranked 15th. The most important reason people chose Sylpheed is:
No issues with stability or stuff going missing.
Ranked in these QuestionsQuestion Ranking
Pros
Pro Reliable
No issues with stability or stuff going missing.
Pro Comprehensive settings
Pro Very very lightweight
It is simple and very lightweight where claws mail added a lot of bloat like themes and plugins slypheed keeps it simple.
Pro Free and paid version
Users who only need to use the basic features of the app have a free version available, though it does limit to only 3 sync'd accounts. There is a paid version that does extend functionality and allows for unlimited account but it does cost $1.00 a month or $45.00 as a one time fee.
Pro You can have multiple accounts
In Pro version, you can create an unlimited number of accounts.
Cons
Con No encrypted mailbox
Likely hasn't been done by anyone since Calypso/Courier back in the 00's.
Con Drag & drop is impossible
Drag & dropping folders and emails between accounts are not possible.
Con Poor import/export of contacts
You can only import your contacts data via CSV, which isn't the most popular choice. Much more convenient ways to do so exist. Even the older Windows Life Mail program is more flexible when it comes to contacts and offers such features as duplicate checks.
Con Collects user data
Mailbird does collect some user data such as user email addresses, names and client use. So for those that are security minded the use collection of this information may not be wanted and can not be avoided.