I don't think they work.
My aunt had it, lost close to 100lb. gained it all back in 9 mo.
A friend had it, lost 80+lbs, gained it all back plus 25(a guess)...Anyway, She is larger than she was.....Another got stapled, went from 200+ down to 140, her friend died and within 6mo she was wider than she was tall.
I personally know three others that had a procedure, same results after about a year.
All 6 people I know had it done just wasted their money because they never changed their eating habits, just how much their belly could hold. The stomach will eventually stretch to fit how much you can shove in there.
I'm not saying the NEVER work, I'm just saying that If a person really has the will power to change their eating habits to the 3 or 4 oz the new stomach can hold for the rest of their lives, they have the will power follow a strict eating and exercise regimine, without cheating, and loose the weight slowly over time, without surgery.
Just MHO