Ive never understood the slippery part 
Nothing Ive had any issue with at least, Ive been using a cintiq for many years, maybe doesnt count?
But the past 5-6 years Ive pretty much only been drawing on ipad and havent felt that problem, maybe it just takes a little getting used.
But seen many that likes that paper like screen protector- only downside seem to be it uses up the nibs more quickly?