Never used them often enough myself to see results but used to work in a health club that had them and they got brilliant results from some of the ladies. The thing is to work with the tables,not just let them do the work. Things like tightening tummy muscles while on the sit up bed etc.
I once used them myself years ago and if you work with the tables rather than just lying on them they can really tone up your body. I would defo use again if they had them near me. I went 3 days a week for 6 weeks