i use their products all the time and i'm thrilled with them.
i only use the iron away pounce and i mark the entire quilt at once and then i load it onto my quilting frame.
i've never had a problem with the marks wearing away and the iron away with ease.
my only complaint would be with their stencils - you can only use them with a pounce type product - pens/markers/etc will not mark a quilt thru this line of stencils.