When comparing Bartender vs SizeUp, the Slant community recommends Bartender for most people. In the question“What are the best power user tools for macOS?” Bartender is ranked 13th while SizeUp is ranked 57th.
Ranked in these QuestionsQuestion Ranking
Pros
Pro Cleans up the menubar so it's less cluttered
Pro Great customisation options for the menu bar
Pro Lean and efficient
Does what it is supposed to do efficiently.
Pro Keyboard centric
SizeUp has user-configurable keyboard shortcuts for a set of pre-defined actions.
Pro Supports multiple monitors / spaces
Windows can be sent to different monitors and spaces. It can also be aligned as needed.
Pro Simple
SizeUp is easy and simple to use without having to configure.
Pro AppleScript support allows extending functionality
AppleScript permits adding features such as tiling all open windows. Additionally, FastScripts it allows the user to add keyboard shortcuts to AppleScripts.
Pro Menubar dropdown for shortcuts
Learning a bunch of keyboard shortcuts right off the bat may be difficult to remember at first, which is why a menubar shortcut for the app exists with all the shortcuts listed.
Cons
Con Expensive
$15 for download or $7.50 for upgrade if you have Bartender 1.
Con Nag window
If a license is not purchased there is a nag window (which suspends function) that pops up when loading the app (at user login). The nag pop-up is also summoned at certain time intervals and by performing a certain number of commands (manually or by keyboard shortcut).
Con No on-the-fly split screen window settings
Unlike some other tiling window managers, SizeUp has no way to change the size of split screen actions on-the-fly. Any time a user wants to change how much room on the screen a window takes up when using the split screen function, they will need to manually change the settings, which can be time consuming.