I second the advice to chose screen printed decals if available. I've used PPS decals on an Indiana Jones (screened) and on a Fish Tales (next Gen) and can speak to my experiences. Both games turned out well and look great, but there are differences.
The screen IJ decals look fantastic with rich colors, good resolution and a smooth glossy finish. The next gen decals have more of a matte finish that fails to give the colors the richness of the screened decals. On close inspection you will also find that the next ten decals don't have the same sharpness and resolution as the screen prints. The causes sharp edges to have a fuzzy resolution on fine details like lettering, but is not really noticeable on larger sections of art. The print on the next gen decals is pretty heavy, enough that you can feel raised edges of the ink much link layers on a screen printed surface.
Overall I prefer screen printed but would not hesitate to use the next gen if that was my only option.