When comparing Opera (presto) vs SeaMonkey, the Slant community recommends SeaMonkey for most people. In the question“What are the best browsers not based on Chromium?” SeaMonkey is ranked 8th while Opera (presto) is ranked 13th. The most important reason people chose SeaMonkey is:
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.
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro Still pretty compatible (not 100% though)
Pro Very fast for such an old unsupported browser
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
Cons
Con Unsupported anymore
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Con Looks very old and outdated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