I used Standard 3DMAX materials to shade almost everything in the scene, exception for the plastic and metal materials. I did those exceptions using Vray materials, a good option to save render time and make beautiful reflection using HDR images.
I used one hdri image as a main illumination and four more omnis to help me out with the specular reflections and to generate four precise specular points at the phones.
I like using Vray render. Many people say it isn't a professional render, but I see it's becoming more robust and steady each newer version. It brings me the quality and velocity I need in my works. To avoid the famous flicking shadows I used the medium animation preset and everything was did in a great style (no problems). In my opinion it's one of the must powerful renders available on the market.