I've tried two of the top devices, and have experienced mixed results. I haven't consistently gotten "hands off" orgasms, or even really enhanced orgasms, though that may vary between individuals. It could be fun to play with a partner, in scenarios from teasing to BDSM, and could possibly provide a way to stimulate a partner who doesn't normally orgasm from penetrative sex.
And you can spend quite bit a more money trying to find electrodes and electrode combinations that really "hit the spot" for you and/or a partner.
Plus I'd second, as suggested in a previous post, that there are concerns that playing with one too much could affect responsiveness to regular sexual activity.
FF