Question about window tinting:

I am thinking of getting my windows tinted so as to add more security and to make my car look better. This would purly be aftermmarked but I am not looking to do it myself. What should I be looking at as far as window tinting is concerned. What I mean by that is is there something I should be looking at or something to stay away from as far as materials are concerned.

Any recomendations as to where to go? I was thinking Ziebart.

Thanks