I've been running my ASUS WL-500W Wireless N Router with DD-WRT for a good two months now.
Here's what I've found:
It works great for me!
I hated my WL-500W with the stock firmware. It seemed clunky and didn't behave all that well, despite updated firmware and a plethora of promising features. But since I had this device at my Dad's house, its original shortcomings didn't mean much to me - it worked adequately for him, so I was fine with it.
But a few months ago my Dad received a "free" wireless access point from his new internet service provider, so I ended up with the WL500W. I decided that DD-WRT was the only way to go.
I installed the Mega Generic, v24 preSP2 (Build13064), available from the DD-WRT web site. I followed these TFTP instructions. Installation was a breeze using TFTP. I was stoked to see it boot.
Issue #1 - making a brick.
I was busily reconfiguring the WL500W soon after it booted: make a config change, save, make another change, save, etc. And then it turned into a brick.
The LEDs on the WL-500W started to flash as if it was in a constant reboot cycle. I became sad; despondent almost. I struggled to use any software technique I could find to unbrick it. After several painstaking hours, I gave up on a "soft solution" to unbricking it.
After so many wasted hours, I concluded that the only way to unbrick it was with a hardware technique. I went after the brick using the pin 9 grounding unbrick method. I've heard mixed reviews on this technique - some have claimed that this method will permanently damage the device. But since I otherwise had a brick, I decided to take the risk.
In my case, the unbrick method seemed to work wonderfully. Phew! The brick was no more. I reinstalled DD-WRT and did my best to...
I think my mistake was saving configuration changes too quickly. Now, when I make a change to the configuration, I give the WL500W a good long while (like a couple minutes) to commit the change to flash memory. I wait until the load average goes down to near zero before saving another configuration change.
I'm not sure if it really helps, but I haven't bricked the router since I instituted my new "slow save" procedure.
I mistakenly tripped power to the WL500W last week, and it didn't come back up: The "AIR" lamp stayed off, and the device wasn't accessible via ethernet. After experimentation, I found that the device would start up normally if I unplugged my laptop from the WL500W's ethernet port when powering up the WL500W. I didn't look into the "failed boot" condition any further.
The other issue is that I could never get the USB ports on the WL500W to do anything useful for me. Then again, the same was true when I used the stock ASUS firmware.
I find that the WL500W performs quite well for a 2.5 GHz-only "N" router. It certainly beats the pants off of many other N-class home routers that I've used.
The WL500W with DD-WRT has been rock solid. I do have it automatically restart weekly, but I have never had any indication that it actually needs to be restarted on a schedule.
And it can easily run with that Mega build. I love having most all of the DD-WRT features on the box. Once you go Mega, it's hard to go back.
Well, I hope that helps!