The hex shape seems to be stronger; I've not done any drop tests or anything like that, they just seem to be sturdier, and they stack better, you don't have to hit the pegs for them to be stable. You can 'slot' them based on the shape of the rack itself.
I like the Apache racks because you can see the chips better, and they fit in the bird cage, I've not sampled the matsui racks.