When comparing SeaMonkey vs Otter Browser, the Slant community recommends Otter Browser for most people. In the question“What are the best desktop web browsers?” Otter Browser is ranked 7th while SeaMonkey is ranked 27th. The most important reason people chose Otter Browser is:
A better license for a browser than a restrictive "all rights reserved".
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro Full internet suite
Wraps all your internet stuff together. It's like it's Firefox and Thunderbird all wrapped into one, and it kinda is. It's the continuation of the project both of those were extracted from.
Pro Not bloatware
Pro Designed for usability, not looks
Pro Under GNU GPL
A better license for a browser than a restrictive "all rights reserved".
Pro Open source
Anyone can contribute to the Otter Browser, solve common issues, bugs.
Pro Legacy Opera
Aims to recreate the best aspects of Opera 12.x.
Cons
Con Bloated with unnecessary features
Seamonkey has a browser, email client, and even an IRC chat. Too much bloat! It doesn't do one thing, let alone do anything well. It should be avoided.
Con Looks very old and outdated
Con No Addons
not a single adblocker or privacy addon that was useful
Con External Rendering Engine
It uses the Qt Web Engine from your local Qt installation which is usually not often updated.
Con No support for addons
Con Under GNU GPL
It is licensed under GPL which is less permissive than other opensource licenses like BSD or MIT.