I too am highly skeptical of ALL of these claims.
My main gripe with Soylent (ever since I first saw it here on HN a month ago) is that they are making cooking seem like a horrible chore that nobody wants to do.
Shopping is convenient because I go whenever I have time and only buy exactly what I need. At the same time, I also ensure I only buy the best ingredients I can at the moment (Assuming labeling is correct).
A lot of people I know and myself included, LOVE to cook. I love cutting a bell pepper and catching a whiff of its fresh smell in my nostrils. I love sometimes adding different sauces, spices or ingredients in my meals to give them a distinct and unique taste.
And cleaning up is also fun because I recognize I am a responsible adult, able to revert something back to the state I received it in. Just like my bed, or a rental car or my home.