Try holding on to it
That looks very nice and is an engineering masterpiece but the ergonomics are horrible.
Lighter, thinner, more powerful seems to be the goal these days but we already have palmtops, netbooks and tablets that are too thin to hold effectively while being used.
I have an ipad which is good for viewing but poor to hold due to weight and lack of thought given to where you hold it.
Lighter and more powerful by all means but please think about how can hold onto it. Digital cameras have done well in finding ways to improve grip and handling without adding bulk why can't ultrabook designers.