Major difference between High Sierra and Mojave
Some of the major news in Mojave are:

Dark mode
Home app
News app
Stocks app
Voice Memo app
New screenshot utility
Group FaceTime
Desktop stacks
Finder Quick Actions
Continuity Camera
Privacy enhancements
Warnings when running 32-bit apps

It is not my impression that macOS Mojave brings along major bugs that haunt most of its users.