I had the same Problem with one of my Clients, and found this GREAT soluiton:
Duplicate Widget.
It comes as a new Widget, but has just one option: choose which Widget it should duplicate, and you also see from where it is duplicated (for easy overview where to change the values of the original Widget). Works like a charm, and you have to do every change you make only once for every sidebar.
I suppose this would be your better yet solution 🙂