DD-WRT

Okay, so I very much misunderstood what DD-WRT does and is. I thought I'd heard that it was a linux distro for the WRT54G, whereas Tomato is a replacement GUI, both of which offered more functionality than the stock firmware. As it turns out, they're both replacement firmwares that offer more features through a GUI; CLI interface doesn't come into play for either of them.

Breaking it down, DD-WRT offers more slightly functionality, Tomato offers cleaner functionality, and better reporting. DD-WRT installs onto more versions of hardware. Tomato is AJAX-y, and restarts services; DD-WRT is Web1.0, and restarts to catch new settings.

Dunno. I'm now running both in the house, as I have a router that won't take Tomato. Both get the job done, and both seem stable. If you don't need the extra functions in DD-WRT, and Tomato will install on your hardware, I'd say go that way.