I'm not an expert on these decals but reproduction cabinet art before next gen was basically silkscreen on a vinyl base. Theses were considered to be as close to the original look due to it being the same process used on the cabinets when they were manufactured. Next-gen is a different/newer process using large printers. I'm sure someone can give the technical details better than me. My personal experience is they are both great looking,silk screening being only slightly more authentic but next gen slightly easier to work with. Less tear /chipping on the cuts.
Boobs working hard to level up this restoration. That said I waste paint sealing the entire cabinet as he has done. Many others will prime all expected surfaces and paint only the exposed areas.This saves quite a bit of produce and cost.Whether you use either method. You need to "lightly" sand the area getting decaled only for the purpose of smoothing out ant slight over-spray or debris that lands on the final coat.This insures no telescoping of the base imperfections associated with painting. IMO