I completelly disagree with you. As you can se, technically the same, Linksys WRT-54GL (just smaller RAM + ROM) was benchmarked:
http://www.smallnetbuilder.com/content/view/26843/51/
And ASUS was not. As usual. So I suspect, there is another reason - for example ASUS dont cooperate with smallnetbuilder... I don know.
I know comparing WL-500gP with DIR-655 si something like apples to oranges, but both of them have their pros and cons. D-link has the best cost-performance ratio with great peformance at all a fastest specifications (1Gb LAN, Wireless N). On the other hand ASUS has usefull USB ports and bulletproof firmware, which can be upgraded to many alternative firmwares and the box cant be bricked.
Both of them cant wake-on computer in LAN, but I can Easilly modify ASUS to do that, using alternative firmware. It uses Linux, so I can ssh on it and use ether-wake or do it from web interface. So I can't buy DIR-655 which amazed me, because it has lack of abilities I need. And no alternative firmware can help, because D-link uses proprietary VxWorks ( example).
So technically, they are different, but with 10M line to internet, there is no diffference between 1Gb and 100Mb router. There can be difference in stability, signal strenght and so on. I was thinking to replace my
rock stable ASUS WL-500gP with something faster, but I have no Idea, how does it stands comparing with other products, so it can be really wrong decision...