I think they're alot like the wired NICs you can install in your desktop. You can get them incredibly cheap, and they may work just fine, or you can spend considerably more money - for not a whole lot more functionality, just maybe some more bundled software or better configuration interface, etc. As with anything else, you can pay a premium simply for a name stamped on the thing as well.......
The biggest thing with wireless would be speed and compatibility. If you buy a wireless g only card, and your router or ap is b only, then there will obviously be a problem. Most g cards I've seen are backwards compatible to b networks though....
Best to find out what the router is and get something compatible, and then maybe do a little research on what works well speed-wise. I've seen g networks that run as slow as b simply because the card is not all that great. But then, wireless depends on signal strength too, so if the router or ap is in a bad location, or isn't all that great of a router, then the best card in the world won't increase your speeds.
Security (encryption) can effect speeds as well. Won't be an issue for internet access and such, but if you want to transfer huge files, it may be an annoyance..
With all that being said, I have had great experience with netgear equipment, and they're stuff usually gets good user reviews....
EDIT : I looked at your link after posting, and that looks to be a decent card. Couldn't find any user reviews on it however...