As an OpenWrt user, it's not for everyone. I was surprised to see it in the running but nothing comes close for a Linux tinkerer. While they have ready-to-go images the real advantage is compiling your own firmware. I'm no developer but their build system is so easy even I can do it.
DD-WRT spews features but under the hood is an extremely creative environment to get the most from the available memory. I'm biased with the nice Linux environment of OpenWrt so DD-WRT looks like a mess - yet it apparently works for many people and has the most features.
Over the years, Tomato seems the most solid for the average user. It's the one I generally recommend.