I've looked into buying a machine the Enagic one ($2500+), not the $99 one on ebay.
From the studies that I've tried to google, there is nothing saying it works or that it doesn't work. But I do know a good amount of people who swear by it. But the issue I have is that these people didn't drink much water anyways. So of course once they start drinking more, they're going to feel better and be healthier. I drink about 1.5 gallons a day.
A few workout buddies of mine said when they mix their preworkout with Kangan water, it kicks in faster and more effective. Which would make sense, because it does say don't take with medications because the body will absorb it to fast.
They do sell alkalized water in the stores, but the problem is that light (sitting on the shelf) reduces its PH levels, and so does agitation (shaking from transport to the store). So I think Menehune claims their water has a high PH level, but the 5 gallon jugs sit on the truck for days and that truck drives and shakes a lot.
So if you're going to Whole foods and buying bottles of the high PH water on a regular basis, then you're better off buying a Kangan machine.
If I had the money to spare, I'd buy 1. But right now, I have other priorities (more guns).