Please note that the driver for the ACX111 wireless on these models is unstable. There are two different drivers available, each with its own limitations, but neither of them is stable enough for general use.
NOTE: AR7 modems have a reputation of running HOT, so if you're planning to run it for any lenght of time, attaching an heatsink to the CPU (or just taking the top of the case off) might be a good idea.
NOTE: After some months of operation, the ethernet switch included in some 5xxT/G6xxT starts to become unreliable (you'll notice a lot of retransmissions and a much slower connection). One workaround is to force the switch to operate in 10Mb/s mode (unfortunately this requires a kernel patch).
This is actually caused by the cheap electrolytic capacitors that smoothe the power supply to the switch IC, which degrade over time (and with heat). Replacing the capacitors fixes the problem. Look for a capacitor of about 100uF, one near each short side of the switch IC (IP175 or ADM6996M), and replace with the same rating.