Just pulled the trigger on an EE upgrade for the 64GB S6 in black. 4GB 4G extra, unlimited calls and texts £43.49 with £79.99 up front. The only thing I'm really kicking myself over is the Samsung store (partnered with CPW) offered the same price but they supply unlocked phones with BTU ROMs. I only remembered after accepting the upgrade, so I'm deciding whether to just flash a BTU ROM from SamMobile and unlock the phone later if/when needed or just cancel the upgrade and go back to Samsung/CPW.
My trusty M7 has been without any case/cover/skin for two years and survived admirably. I don't think the S6 would fare the same. What's the next best thing to being naked? I just want to protect the camera and glass so something like a slip on skin I suppose.