When comparing BetterSnapTool vs Spectacle, the Slant community recommends Spectacle for most people. In the question“What is the best window manager for Mac?” Spectacle is ranked 4th while BetterSnapTool is ranked 7th. The most important reason people chose Spectacle is:
Spectacle is licensed under MIT with source code available on [GitHub](https://github.com/eczarny/spectacle).
Ranked in these QuestionsQuestion Ranking
Pro Custom Snap Areas
With this feature, you can move any window into the desired position, select 'advanced: create a custom snap area (using current window as template)' from the toolbar and also edit settings for the snap area. It is also possible to edit the size, position, and presentation of the drop-zone, the shortcut for the custom snap area, and a list apps for which the snap area should be available (eg: only show this zone for VLC).
Pro Free and open source
Spectacle is licensed under MIT with source code available on GitHub.
All windows in Spectacle can be controlled with keyboard shortcuts, so no mouse is needed. This makes for a fast way to control windows.
Pro Low footprint
Spectacle only uses up 18-19 MB of RAM, which means there is not much overhead by using this app.
Pro Simple hotkeys
Spectacle offers easy-to-remember preset hotkeys.
Pro Great UX
Spectacle is easy to use and configure. It's plug and play.
Pro Multi-monitor support
BetterSnapTool is no longer free and now costs $3.
Con Impossible to add new functions
While keyboard shortcuts can be changed for the available actions, there is no way to add custom actions which in turn limits the functionality of the app.
Con Limited window sizing capabilities
You can use 1/2 of the screen vertically and horizontally (divide into 4 parts). You can also use the screen in thirds too, but only the left and right third: you can't use the 1/3 in the center. There is no way to do a more granular distribution.
Con Doesn't work with any Adobe products
There are some apps like Adobe Reader that do not work with Spectacle. Basically, any app with a heavily customized UI that breaks OS X accessibility will not work correctly under Spectacle.