I ended up using the 3M IJ35C because it was a long term application. I thought it would adhere better than the removable vinyl or static cling material.
I'll tell ya what, though those static cling products you mention, if you're referring to such material as Glass APeel (formerly GlassAdHere), are pretty darn amazing and the smooth as butter matte finish looks so much more high grade than vinyl/gloss laminate with it's slight orange peel texture. We've been testing it out on our own shop
windows for over a year now and our window 'posters' look every bit as nice as they did when we first put them up. The low cost, removability, and reusability are what I really like about this option over standard adhesive vinyl products. Customers can also easily install it themselves and it's a decent alternative to vehicle magnets.