From DD-WRT Wiki

Hardware

You can tell which Rev of the hardware this router is from the box (it will say "H/W Ver: C1 F/W Ver 3.01" for example on the bottom of the box, underneath the barcode). A similar sticker with the hardware version and firmware version is also stuck on the bottom of the router itself. This means it's quick and easy to check the hardware revision before buying or borrowing it.

The factory default IP for this router is 192.168.0.1, user is "admin", password is blank.

Pros of this hardware

• 4 MB board, so no need to use "micro" DD-WRT builds.
• Fairly inexpensive.
• Fairly new hardware (released in 2009?), so it's widely available for purchase new.
• Reasonably fast CPU clock speed.
• Easy to install DD-WRT on this hardware (just flash through the web interface as per below, and you're done).

Cons of this hardware

• No USB port, so cannot be a NAS for a USB drive, nor can it be used for Printer Sharing of a USB printer.