I'd like to see that used on a plane in economy. Given that I travel a lot and don't always end up in business/first, this is one of the first questions I ask myself when considering any new laptop.
Not so much size, but weight. If your carry-on allowance is 7kg and you don't check baggage, having a laptop that weighs 3kg like the Vostro 17" is a big deal. If you've got a heavy laptop, you've got to either bring less stuff with you on your trip, or go through the hassle of checking baggage.