I've always thought these devices were way overpriced for what they do.... and I still think the $50 ones are...... but at 30 bucks, I had to try it. And man am I glad I did.
This is one of those items you buy and immediately think to yourself, "Why didn't I get one of these years ago?"
It does what it say it does. The magnets are strong enough and the easy on/off switches are *so* much easier to deal with than turning knobs on a bolt to tighten and loosen a standard featherboard.