The trick for sealtite is to use the tool to make the cut in the metal, then use a knife to cut the rubber/pvc jacket around the sealtite at that point.
For larger sizes, you can USUALLY do the same thing using an angle grinder .... I say 'usually' as I have encountered 4" sealtite that was not made as a spiral wrap, and I had to cut all the way around it.
My one complaint about the roto-split tools: they are gray in color, and far too easy to misplace. I have found it necessary to paint mine the brightest colors I can find.
