Can You Believe Me Now?
This article here says WiFi chip makers are producing products that intentionally interfere with their competitors products. These so-called "Turbo" mode products promise speeds double the usual 54Mbs of 802.11a/g. But if a competitor's system is operating nearby, the interference caused by the systems will effectively slow or even block all transmissions (unless, of course, you switch to their brand of chip).
A pox on all their houses I say. I disconnected my Linksys access point and got a Microsoft one instead. Not only do I get higher throughput without "Turbo" mode, I also get greater range.