Caffeine and alcohol have horrible side effects on my mind, and my body. I didn't realize for years, about the caffeine. I don't know about this kind of electrical stimulation. The fear that I wouldn't have the predictable kind of control over the growth and direction of my neural connections doesn't sound like something I want. I tend to think of these things in terms of trade-offs though.
I personally do not think it is very intelligent to place control over a highly sophisticated organ in the hands (or brain) of another being, unless I am certain to trust that being in that they know what they are doing. Very generally, it just seems like allowing someone else to manipulate, shape, and mold my mind, without me having a choice over it. I don't know if that is paranoia, or a kind of 'survival of the mentally fittest'.
I know that when I feel like it is highly probable that I have been duped into thinking a certain way because someone else thinks it better for me, and I find out that they intended to do this, there is a certain kind of rage that manifests in me, that is unlike any other. It begins with the assumption that they thought they were more intelligent than me. I've thankfully never been proven correct on this, but I tend to disconnect from people that don't have the ability to maintain a constant of mental equality throughout interaction. This is fairly tangential to the topic, but I think it's somewhat relevant in a broader context of the potential consequences of science poking at the brain, without understanding how the brain might fight back.