The biggest complaint I hear about minimalist shoes: the price. I see the logic, there's less material and "engineering". I make my huaraches for about $10 a pair ($7 for the rubber, $3 for the rope). Minimalist shoe companies, like Vibram FiveFingers and Merrell Barefoot, advertise that they don't engineer their shoes, which begs the question, "then what are we spending the extra $80 on?"
Well, the truth is that there is a lot of engineering that goes into a minimalist shoe. It's just that the engineering doesn't focus around correction and stability; it focuses on freedom of movement and durability. If it isn't apparent, putting a shoe on your foot is at odds with maintaining the barefoot "feel". So minimalist shoe designers have to figure out how to protect your foot (from sharp objects, elements, etc...) while using as little material as possible to maintain as much feedback from the ground as they can.
So once the engineers have made a shoe that is as minimal as it can be while still providing protection, they have to figure out how to make it last. If designing a shoe that feels like you're not wearing one is tough, making that shoe durable is tougher. My huaraches make my feet feel pretty darn barefoot, but they never last long (really inconvenient when you're out on a run, though I admit that I am no expert huarache-maker). Vibram is constantly trying to improve the durability of their shoes while maintaining that barefoot-feel. When I go on a long run, I wear my Vibrams because I know that I won't be limping home with half a shoe.