Derek and I agree on one thing at least: disposable cups are a big problem. They are not recyclable (the plastic liner makes them a "monstrous hybrid") and they pile up in landfills by the billions. Coincidentally, we show two reusable cups that are competing on Kickstarter. They demonstrate two completely different attitudes towards design.
Robert Knox's Cortica is made from all natural materials: cork and porcelain. It is lovely to look at and the porcelain is protected by the cork, but Derek says " it would quickly end up in pieces in my hands."
Ben Melinger's Smash Cup is unbreakable and collapsible. It is made of food grade silicone. (really people, only polycarbonates had BPA, you don't have to preface the word "plastic" with "BPA free" every time you use it). It is easy to carry around in your backpack.
They are both clever designs. Which do you prefer?