I didn't know about Asus laptops when I bought mine (an eMachines M6811), but at the time it was about the most power per dollar you could buy. Sager, for instance, didn't sell anything comparable, at all. The Athlon 64 3400+ (an ancient processor design in computer years) is *still* faster than any mainstream Pentium-M, the Radeon 9600 was near top of the line then, the battery life's three times better than the P4 space-heater machines that were the only competition in power, and the price ($1250 with rebates) was great.
I suppose there are three categories of people who get namebrand machines: those who do their research and find them drastically on sale, those who want that particular set of features (usually business-oriented), and those who don't know all their options.
It seems that the quality/price of the non-branded machines has dropped drastically recently, though. Good luck finding anything with an x700 at Best Buy that can compete in price with the MSI 1029, or any machine from a name-brand vendor that has the combination of features of the Asus Z71V/Z70va.
If I were in the market now, it'd be the Z71V, no questions asked, unless someone came up with a Turion with an extended battery.