The stuff's so much cheaper down there than it is in Canada. The legs are $16 for the 4 inch ones. I'm considering building one with the 6 inch legs. Too high? Also, do the legs include the mounting screws?
I think it's all about personal preference.
I personally don't like looking upward towards my monitors and that is why I went for the shortest height possible, the 4".
Also, too high and it might be unstable.