I don't think this comparison is reasonable because the size of index at google is much larger than bing's. For some simple just for test queries, bing's results may seem to be better but in the real world a much larger index is much much more important.
I tried Unison before and gave it up. Not because it is not a great software. But because two way sync itself is very dangerous in my eyes. If I made some stupid mistakes in one side, my all data gone.