There doesn't seem to be anything in there that can't be achieved for less money with dextrose and CaraPils.
My experience with Munton's Carbtabs, which seem to be pretty much the same thing, has been pretty negative: Slow carbonation and lots of floaties in the beer.
The Fiesty(sic) Goat Brewery est. 2007 & Clusterfuggle Experimental Ales est. 2009
Primary: Saison, Berliner Weisse, sLambic I, sLambic II, IPA, 70/-
Secondary: Orange Blossom Mead, Flanders Red I
Kegged: Fat Man Porter w/ 1469, Fat Man Porter w/ 005, Centennial Falcon w/ Conan, Centennial Falcon w/ Denny's, Barrel-aged Fat Man Porter, Belgian Dark Strong, Dark Mild