I have one flashed with the latest DD-WRT Pre SP2 Beta.
It works ok, but the range is not as good as the WRT600N. It also gets VERY HOT, so you need to shim up the tail end to provide extra ventilation. ( I think most users probs with this unit stems from over-heating ) I think once they get a final v24SP2 dd-wrt, then the Linksys WRT610N would be a good choice. It has 64MB ram and 8MB Flash.