Inside the MN-500
Some of the news coverage of the BroadBand product launch reported that the 802.11b wireless products use the Intersil PRISM chipset, which you'll see I was able to confirm. But with a little detective work from Christopher Lee, and with Microsoft's help, I'm able to give you some additional details of what makes the new Microsoft "Base Stations" tick...
Digging through the FCC Exhibits for the MN-500, I found that the Internal Photos document has some nice shots of the product's circuit board. I've cropped these a little and included them below for your convenience.
Microsoft MN-500 Component View (from FCC Internal Photos exhibit document)
Microsoft MN-500 Component View - No RF shield (from FCC Internal Photos exhibit document)
I guess someone thought they'd at least try to introduce a little mystery, but forgot to change the first photo! At any rate, the photos show that the MN-500, and I'd expect the non-wireless MN-100 router, join the ranks of the D-Link DI-604, 614+, 764, Netgear FR114P, SMC7004VBR, 7004VWBR, and plenty of other current-generation routers in their use of the ADMtek 5106 Home Gateway Controller.
This is a nice deal for Accton, but maybe mixed news for Microsoft, depending on who Microsoft chose to do their firmware. It seems that most of the ADMtek products have had their share of bugs, including problems with SPI firewall features and throughput, and Inbound port forwarding. This doesn't necessarily guarantee that the MN-500 and 100 will share this fate, but my rule of thumb says to expect at least some problems as the product gets a real-world shakedown.