I've had this router for over a year now with zero issues.
Lately I've been having problems with my internet though. I'm able to connect to Xbox Live, use bittorrent clients, play online games, and do just about everything possible with a cable connection. After a few hours though, suddenly my ability to load webpages degrades considerably, often taking several times longer than usual to load anything.
After another few hours I lose the ability to load anything using any browser. Everything else still works fine.
I've tried several different firmware versions, including official ones from Linksys as well as DD-WRT and HyperWRT but no matter the firmware the same thing happens.
I pull the plug on the router and when I plug it back in I'm able to browse like normal again. Then once in a while when I plug it back in the connection craps out completely and I have to hit the reset button to get it to work again.
I've tried connecting directly with the cable modem and that works just fine. I've also tried turning on QoS and making HTTP traffic a priority: same problems.