One of the things people have said about these cutters (the Cameo and now the Brother) is that the blades dull pretty quickly so that corners don't go well. Also, the Cameo at least seemed to have some reliability problems, but Brother puts out some of the best printers (which this essentially is) and so I'd trust it more than I do the Cameo for that reason.
But I have my doubts that it will replace the Accu-cutters. It will just be another tool in the arsenal, as they say.