I personally don't think it's a matter of some systems being superior or not. I think it's a matter of whether or not these types of devices are capable of removing heavy metals from the feet or not, but I remain open-minded.

It's good that this company did a study. Now, I'd like to see it repeated by a disinterested third party. I'll tell you right now, I would love to find out that they really remove heavy metals. If I believed that, I would manufacture them myself (with my embedded systems background) and become a millionaire in a few years.

(Actually, I just checked and did not find any study on their website. Do you know where I can find it?)

Unfortunately, we have done our own study:

http://herballure.com/Studies/IonicFootSpa.html

and found no significant effect concerning heavy metals. Again, I wish we had.