> pci will be faster

Not likely in any functional sense, I believe. USB 1 is fast enough
for internet. USB 2 is more than enough for anything. The wireless
connection itself will likely be the bottleneck for local network, the
ISP when going online.

>and you wont have to contend with outhr usb devices

Is there such a thing as USB contention? You mean that a port will be
unavailible for other devices. But only IF ports are in short supply?

> some usb chipsets have problems my shutlle had problems with the
> linksys usb adaptor

That makes sense. My Linksys USB "B" adapter works most reliably of
all my devices, though.

Anyway, The Advantage of using USB is putting a cheap no-loss extension
on it and getting it up higher for clear reception line. Almost no
cost, no antenna or lossy cable. One of our desktops is doing this
and it makes a huge difference compared to the PCI adapter on the back
of the PC with it's antennas buried behind the metal box.

If you are close to the AP, then it may not matter.

Steve