When comparing Mu4e vs SOGo, the Slant community recommends Mu4e for most people. In the question“What are the best self-hosted webmail clients?” Mu4e is ranked 3rd while SOGo is ranked 6th. The most important reason people chose Mu4e is:
The UI is designed to allow for quick keystrokes to get around and is pretty clean. Header View:  Message View: 
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Pros
Pro UI optimized for speed
The UI is designed to allow for quick keystrokes to get around and is pretty clean.
Header View:
http://www.djcbsoftware.nl/code/mu/mu4e-2.png
Message View:
Pro Asynchronous
Heavy actions never block emacs, unlike most other emacs email clients.
Pro Fully Search Based
Mu4e has no folders or other organizational tools, rather it relies on very fast search queries to help you find your mail.
Pro Can write rich text emails
Using the (beta) org mode, Mu4e can compose fully rich text emails.
Pro Built-in Autocomplete
Doesn't require you to import address books for autocomplete, learns from your emails just like Gmail.

Pro Drag and drop interface
Folders, contacts and events can be moved around with intuitive drag and drop functionality.

Pro Calendaring and messaging data can be accessed via web and multiple desktop and mobile clients
Pro Microsoft ActiveSync support

Pro Localized
Available in 30 languages.
Pro Fully responsive
The UI is fully responsive, and works fine on desktop, tablets and phones.
Cons
