On the majority of work it is. Small windows can't really save any time like new builds but large panes of glass really notice a big time saving , using less water and less effort. Does take a while to get use to changing the way you clean windows with it but once familiar it becomes second nature.
The two main differences between a constructor brush and say a Gardiner brush with an overhead bissell bar spray is the constructor brush is heavier but more suitable because of the additional four side jets for reaching into the corners and the Gardiner adapted version is lighter but with only the rinse bar above the stock but work sufficiently. Use the bissell bar on 5 storey work no problems at all.