As a fan of handlebar cages, I own one of the well made Minoura adapters that let you use a regular cage on the handlebar. It's a very solid bracket and not a bad solution.

I will say that I think the TA bar cage is a better solution than mounting a conventional cage to the bars. The key difference is the loop of wire that extends upwards at the front of the cage....




This helps guide the bottle back into the cage, making it a bit quicker and easier compared to a conventional cage.

That little loop also provides the springiness to grip the bottle. The designs that just have a solid ring of wire around the bottle will either allow the bottle to rattle around in the cage or won't accept a bottle that is slightly larger. Trust me... you want a bit of grip! Otherwise, the first bump will launch that bottle out of the cage and onto the road.

Steve in Peoria
(illustration borrowed from the 11th edition of the Cyclo-Pedia catalog, drawn by D. Rebour)