When comparing Rambox vs gnus, the Slant community recommends gnus for most people. In the question“What are the best native e-mail clients for Linux?” gnus is ranked 14th while Rambox is ranked 17th. The most important reason people chose gnus is:
Yep, really. From Outlook-mode, where Outlook-typical TOFU mails are “repaired”, up to a high-sophisticated scoring and SPAM filtering, footer lines with quotes, rules depending on the recipient, MIME formatting, boxquotes, etc.
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro Cross-platform
Pro Free and open source
Pro You can add personal webs if it not available in the app store of rambox
Pro A lot of apps
Pro Everything is customizable
Yep, really. From Outlook-mode, where Outlook-typical TOFU mails are “repaired”, up to a high-sophisticated scoring and SPAM filtering, footer lines with quotes, rules depending on the recipient, MIME formatting, boxquotes, etc.
Pro It supports IMAP and POP3
… but you can use DavMail to connect to Exchange server via EWS.
Cons
Con Difficult documentation
Originally a newsgroup reader, so its documentation uses Usenet terminology for everything -- which is confusing.