I used one in the past. I borrowed it for a month or so.
It's a tool nothing less. It helps with the takeaway and trying to keep it from breaking.
I don't know if I would pay alot for one but it's not junk.
I would say there are probably better training aids available.
I really like the PlaneMate that has made a big difference in my swing this year.
I have one laying around some where. Been several years since I used it. I trained with for several months, and it definately helped my overall swing. Especially my swing tempo.
On another note, I knew a low, single digit golfer who couldn't swing it, but still had a great, low scoring game. Go figure.
I'd recommend it for the more serious golfer looking for a correct swing.
One thing is for sure. The person using it needs alot patience while learning to swing it.
The joke when I was using it was the higher my alcohol medication level, the better it worked for me. It was an evil club.