I only buy Asus routers, now, but when I had a Linksys, I only used DD-WRT firmware on it.
I now use a different alternative firmware on my Asus.
i put FreshTomato on all my routers ... rock solid stable compared to almost all vendor firmwares, which for the most part are so loaded down with useless garbage that they barely seem to work ... and the absolutely worst thing about these SOHO routers is that they INSIST on phoning home and trying to force you to establish a login account with the vendor ... interestingly, wiki claims ASUS uses tomato as the base for their router firmware, ASUSWRT ...