I was looking for a good and inexpensive "simultaneous dual band" 802.11n router on the market that I could upgrade to DD-WRT or Tomato firmware. The short story is that there isn't one that I could find - all of them are either "single band" or not DD-WRT capable. At least not for cheap money.
So I went in the opposite direction last month and bought myself an Apple AirPort Express. No, it doesn't support DD-WRT, but it is a simultaneous dual band device, and the price is about $95 - which is very reasonable compared to the other "non-lousy" WIFI access points on the market.
I've been using DD-WRT for years, and I've refused to buy a router that didn't support it. DD-WRT gives me a lot of flexibility and power that you can't get with stock firmware. So going in the opposite direction with the Express was certainly a change of behavior.
In contrast to my DD-WRT devices, the Express is much easier to configure and use. It is actually a near-zero brain power operation to get an entire network on it. And it is extremely reliable and very fast. It covers my three level, 4000 square foot home perfectly well... and my 23 WIFI devices work perfectly with it.
The DD-WRT things I miss is short but significant: I miss the traffic utilization charts. I miss logging into my router over SSH and doing UNIX things there. But I love the fact that I don't have to waste my time configuring my router, and the Express has built-in has remote administration capabilities that are a pleasure to use.
In the end, I love the Airport Express. It isn't a replacement for DD-WRT, which I often use as an "always-on Linux host". But the Express is a simple, rock-solid device. Unlike DD-WRT, it hasn't crashed on me yet, and doesn't need a periodic reboot. It is the best WIFI router I've used.