I have the DGL4500 hardware version A2 with firmware 1.21B3. I have 2 wired Macs, 1 wireless mac, 1 wireless XP PC, 2 wired DVRs, 2 wired XBOX 360, 2 wireless PSPs and 2 iphones connected to the DGL4500. So far so good. My ISP is RoadRunner and my speeds are 1 mbps upstream and 20 mbps downstream.
Last night my sons fired both 360's and played on xbox live while I watched the live stream of the KISS concert. I did not notice a single video hiccup and my kids never dropped their live connection.
Here are some traffic stats.
LAN Statistics
Sent :19468481
TX Packets Dropped :9
Collisions :0
Received :15775242
RX Packets Dropped :0
Errors :0
WAN Statistics
Sent :15734702
TX Packets Dropped :0
Collisions :0
Received :25206313
RX Packets Dropped :0
Errors :0
Wireless Statistics
Sent :85686
TX Packets Dropped :529
Received :21218
RX Packets Dropped :0
Errors :601
Connection Up Time: 4 Day 1 HR 07 Min