I agree that the default theme and the glow effect are unpleasant, but once I've switched from Air to Oxygen (Workspace Appearance -> Desktop Theme -> Oxygen) a

I agree that the default theme and the glow effect are unpleasant, but once I've switched from Air to Oxygen (Workspace Appearance -> Desktop Theme -> Oxygen) and removed the glow (Workspace Appearance -> Window Decorations -> Configure Decoration -> Shadows tab -> uncheck 'Active Window Glow' box), things suddenly look a lot nicer.