It looks like Belkin's Linksys unit will have it's own 4x4 router soon to go up again the R7500 and Asus's unit. The Linksys E8350 has the same chips as the R7500 (QCA's IPQ8064, QCA9880 and Quantenna's QSR1000 solution). It looks like the E8350 will have 512MB of RAM VS the R7500's 256MB.
How you have concluded this statement?