I am currently using the SGP Ultra Optics on my 4S and its a great protector but all my TPU cases bubble it up a bit. I decided to order the Speck ShieldView the glossy version. I used the Matte version on my iPhone 4 and really liked them. They are cut extremely slim so no cases give me any problems with bubbling it. A can of compressed air also goes a long way with no dust. I also use this method to install my screen protectors perfectly with no issues: