When comparing Spectacle vs Snagit, the Slant community recommends Snagit for most people. In the question“What are the best screen capture tools for Windows?” Snagit is ranked 4th while Spectacle is ranked 10th. The most important reason people chose Snagit is:
Allows you to adjust the capture, add captions and symbols (arrows, boxes etc).
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro Free and open source
Spectacle is licensed under MIT with source code available on GitHub.
Pro Simple hotkeys
Spectacle offers easy-to-remember preset hotkeys.
Pro Mouseless
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 Great UX
Spectacle is easy to use and configure. It's plug and play.
Pro Low footprint
Spectacle only uses up 18-19 MB of RAM, which means there is not much overhead by using this app.
Pro Multi-monitor support
Pro 7+ years of use
Using it for 7 years
Pro Includes an image editor
Allows you to adjust the capture, add captions and symbols (arrows, boxes etc).
Pro Good markers for setting the capture area
Simple to choose between full-screen, window or a selected area.
Pro Can easily add annotations
The editor allows you to quickly and easily mark and annotate the screen capture.
Pro Can capture screen video
Pro Integrates with third party services
Google drive, Twitter, Facebook, email etc.
Pro Allows for delayed capture
Allows you to arrange the screen as you want it captured. Things like opening a popup menu, to have it part of the capture.
Pro Can capture editable text
Just about any text on the screen can be editable text. I say "just about" because it's like OCR software in that unusual and extra fancy fonts or text against a low contrast background may be a challenge. But overall it works in most situations.
Pro Mobile app for easily moving screenshots from smartphone to Snagit's editor
Cons
Con Not maintained
The software is free, but no longer seems to be maintained.
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 Breaks on macOS High Sierra / Chrome or Firefox
Doesn't support side by side windows.
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.