That's odd because as far as I'm concerned (along with MILLIONS of other people around the world who aren't seduced or blinded by an Apple logo (ergo sheep!), I have no problem with the plastics used by Samsung, I don't find them cheap and I don't find the phone as a whole to feel anything but quality. Of course it's not made of metals like the iPhone, but then again it doesn't scratch before it even comes out the box (!!) or look like a mish mash of design. The S4 has a GLORIOUS screen, is feature packed and I'll live with a pastic back to ensure it remains thin, light and allows me to easily remove and replace, add SD memory, wireless charging etc. if you'd rather have a scratched aluminium back then enjoy!
I'd also direct you to any of the new Nokia mobiles (windows), Sony, HTC ... I could go on ... MANY phones that no, aren't made of aluminium, but sure feel as good if not better than an iPhone, and all are a better usage experience.
How about you either get an apple logo etched on your arm, or open your mind and explore the possibilities from other manufacturers as I and many others have. I still buy Apple kit, but where ts not the best, I vote with my wallet, and for mobiles, sorry Apple, you ain't getting it anymore until you do better.
Anyone else want to harp on about a plastic back????