Wireless cards are tricky. First of all, the most important factor in a wireless card is something that almost
no manufacturer will talk to you about
: transmitter strength. Transmitters are measured in terms of milliwatts. Almost every single card out there is horridly weak -- about 30 mw or so. In practice, this is barely enough to work inside a house or an office.
There are high-power cards out there, weighing in at about 200 mw.
These are the cards you want. You'd have to put it in the PCMCIA slot, but if you were in a position where you needed the extra reach (such as at a WiFi hotspot), this shouldn't be too terribly inconvenient. Check out
http://www.macwireless.com for a 200 mw option.
It's been a few weeks since I did a survey of cards out there. I don't think there are any 802.11g cards that are in the 200mw range yet. If there are, they'd be PC cards. No problem with that, though, as I understand there is an opensource WiFi driver floating around on SourceForge that makes most of them work on a Mac.
Bottom line, though: high-power cards make a
huge difference in connectivity, stability, and yes, speed. I wish I could say how powerful the transmitters in the APE cards are, but I haven't found a good source for that info in a while. I could have sworn I saw them at 31.6 mw, which would make sense, but I could be wrong.
Also remember that the transmitter has to be strong in your base station, too. Your performance will only be as strong as the weakest link in the chain.
For a good hardware comparrison of wireless devices, see
http://www.seattlewireless.net/index...wareComparison
Mark
P.S.: If you have any comments on the info up there, like if I got something horribly wrong, I'd love to hear from you.

I welcome criticism.

Besides, this stuff is hard to learn about.