The documentation... its crap and the support... well none... and debugging well forget that too...
I found it great for solving the problem of small Home office situations with multiple PC's even managed to get Net meeting working through it. Seemed easy to get going especially with DSL.
Problem 1 DHCP server seems to go off line after 1-2 days in which the LAN side PC then can't access the router without rebooting the router. Fixed this by at least one PC with static IP address.
Problem 2 (which appeared after problem 1 work around) after running for a while (1-2 days) WAN access goes very slow which again needs a reboot to fix problem.