The "top" rating is being based on the new trend of portability,
. coupling with longer battery life (Asus),
. simplicity in design (case in point is the HP model mentioned) for business community,
. sleek design (Apple, Toshiba),
. good price/value ratio (Acer) and
. pure powerful machine (Alienware m17x).
In a nutshell it is taking from which model from which manufacturer that stands out over the rest of the pack, and not necessarily the sales of the notebooks in question. But then one cannot ignore the in-road made by Acer, Apple macbook, Asus and the resurgence of Alienware with this latest gaming machine.
cheers ...