When comparing Xfce Whisker Menu vs DockbarX, the Slant community recommends Xfce Whisker Menu for most people. In the question“What are the best app launchers for UNIX-like systems?” Xfce Whisker Menu is ranked 6th while DockbarX is ranked 10th.
Ranked in these QuestionsQuestion Ranking
Pros
Pro The most simple and convenient app launcher on my experience
Pro Built into Xfce desktop environment
Pro Easily customized
DockbarX has inbuilt settings that allow the user to easily customize the look of the dock, from changing the text color to the background color.
Pro Great plugin to help blend in to XFCE4 panel
DockbarX has an available plugin called "DockBarX Xfce4 Panel plugin" that allows DockbarX to blend in seamlessly with the XFCE4 panel, which is great for XFCE users due to the limited options of the default panel.
Pro Easily the best Win 7 taskbar functionality
If you want a combined launcher/manager, a la Win 7, this is it.
Cons
Con Will not support file search
Limited to application launch: https://bugzilla.xfce.org/show_bug.cgi?id=11551#c2
Con Not actively updated
Less than a dozen updates since 2014: https://github.com/M7S/dockbarx/commits/master