When comparing Seamonkey vs Otter Browser, the Slant community recommends Otter Browser for most people. In the question“What are the best web browsers for Windows?” Otter Browser is ranked 9th while Seamonkey is ranked 21st. 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 Not just an e-mail client
Seamonkey is more than just an e-mail client as it is a full featured web browser as well. This makes for a good app to use for those that dislike having many different apps on their devices as it is a bit like an all in one solution.
Pro Auto imports setting from Thunderbird
For those that would be making the switch from the Thunderbird e-mail client setup is quite easy with Seamonkey as it auto imports all previous Thunderbird settings.
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 Permanent CPU usage
Seamonkey permanently uses CPU (quite a few percents on a Intel i7). On a laptop this causes the fan to run (which make noise) and the battery to lasts less time.
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.