When comparing Falkon vs Firefox Nightly, the Slant community recommends Falkon for most people. In the question“What are the best desktop web browsers?” Falkon is ranked 18th while Firefox Nightly is ranked 30th.
Ranked in these QuestionsQuestion Ranking
Pro Access to new features
Nightly comes after beta which means you get access to more features.
Pro Blazing fast
Short load times. Quick tab switching. Fast rendering.
Con Now under the KDE umbrella
Qupzilla is now discontinued and renamed to Falkon. It will also now be a part of KDE and will probably need more dependencies like kde-frameworks in the future.
Con Bookmark management not the strongest part
It often requires quite a lot of clicks to add and remove bookmarks.
Con Weak multimedia support
It has some issues with multimedia content eg. Non-playing videos on webpages.
Con Nobody uses it
Con Buggy; performance issues and crashes
Because you're accessing new Firefox features, bugs and crashing comes. Firefox Nightly is meant for developers and it's for PCs that have low chance of getting attacked. If Firefox is for you, go for the normal one or beta at least. If you use Nightly, checking updates regularly is recommended.
Con Not intended for general use
This browser was made for testing purposes for future versions of Firefox, and it can easily crash. Most people should use the stable release of Firefox.