Regenerate creates an "enamel like layer" very very thin not visible with the naked eye - over the surface of the tooth helping to reduce sensitivity etc - as soon as you cease using the product this layer is gradually worn away.
sensodynes repair and protect does the same thing but is a fraction of the price
I would go for the sensodyne, that works by filling tiny holes that appear in the enamel thus stopping the sensitivity. I had terribly sensitive teeth and use only this it works. If I stop using it and try another make back comes the sensitivity sending my teeth on edge.