Here's an article that made me think about this thread:
Lizzie Widdicombe: Could Soylent Replace Food? : The New Yorker
The story of Soylent the company (basically Ensure with most of its calories coming from grains rather than sugar, making you feel more full) is a pretty entertaining read as a kind of tongue-in-cheek "Silicon Valley start-up aiming to 'disrupt' food" profile.
As a concept, it was interesting how the product itself (which in true techie fashion is open-source, endlessly modular, has a hyper-futuristic 'endgame'/insert other catchphrases here) is mostly agnostic about being vegetarian/vegan/paleo/etc., but still touches on a lot of the topics we debate when discussing different diets - finding the best balance of macro and micronutrients, whether something natural/organic is intrinsically better for you, the land/carbon cost of modern agriculture and what that means from a climate perspective, how feasible it is for people from lower economic strata to eat healthily, to name a few.
I don't think I could personally be a Soylent user since I'm more of a novelty seeker when it comes to food, but I could think of a few people I know for whom eating/preparing food tends to be too much of a chore who'd appreciate the step up in nutrition from eating out/pizza/ramen in addition to the time/money savings.