We've had 646 for 4 years. We don't "cut" label stock with it but we kiss cut vinyl label stock using the cross perf tool (CPM) and rotary tool module (RTM) with the kiss cut blades installed. If you can maintain the habit of wiping the blades off after the runs just like a normal guillotine paper cutter cutting label stock, you'll have success with short runs, if you don't you'll kill your slitter blades quicker and track the label gum through all the rollers. We cut the label stock to the size we want to kiss cut and do up to 2500 sheets approx 8.5x14 in a given day - project comes around every 2-3 months. But you have to keep wiping the blades and slitter wheels off. We don't use use the 646's guillotine cutter on this project.
