They actually reviewed one of those in the news years ago. Not sure if it was the exact same model, but it was the same type of contraption and they were surprised because it worked really well!!
I cut my own hair using electric clippers like the one below. If your hair is all one length and short like a buzz cut then you can just buy some clippers and cut it yourself. Its real easy if its all one length. The only downside is that you have to lay down a plastic sheet made for painting and wear clothes that you won't mind getting hair on.