i remember that i had worse performance with wrt54gl until i switched to dlink dir-655. and that was a few years ago. even though ps2 doesn't need high bandwidth, the router's performance is important. and the quality of network cables.
coming back to the topic of bugs :
i have an longstanding issue with pc-side hdl_dump client - if cpu load is relatively high, the transfer rate drops significantly. even if i/o is not saturated.
on vanilla 0.9.1 transfer would drop from 3.1 to even 1.2 mb/s if my cpu was somewhat busy. even light webbrowsing makes transfer rate drop a bit. concurrent network transfers do not impact the transfer rate, though.
i forgot to mention, this is on linux. maybe windows client has the same issue?