I use mine for just 10 mins to relieve a head ache, its easy to use, didnt cost the earth, doesnt pretend to be magical or anything silly & originally designed in Australia. I've found it works on bald heads as well as haired heads! and everyone i've given one to loves them :)
cheap and effective

Title says it all really. Maybe it's my technique or my head has been out in the sun too long but it just feels the same as Brushing with a metal comb. Might be different on a bald head would be interested to see further comments. Wouldn't even give it to someone as a cheap secret santa pressie. $8 I should have known better. Might make a good egg whisk.

just a waste of time