Apple has always "thought different" in its approach to Wi-Fi router design. The latest incarnation of the AirPort Extreme (earlier 802.11g and nongigabit 802.11n versions have similar names, so be careful when shopping) has dual-band support, but can run only in one band at a time: You must choose either 2.4-GHz or 5-GHz mode.
Why would anyone pick the Apple unit over the Linksys Dual-Band Wireless-N Gigabit Router With Storage Link WRT600N, a model that can handle both frequencies simultaneously? Well, the AirPort Extreme has two key features that the Linksys Dual-Band does not: wireless range extension, which enables users to cover large areas by using multiple AirPort Extremes or Airport Expresses as access points; and USB drive and printer sharing. It's also slightly less expensive than the Linksys.
With the AirPort Extreme, you might keep an older g router for b/g clients, and use the Apple router as a 5-GHz access point for video and other high-bandwidth tasks with 5-GHz 802.11n clients. When operating as a 2.4-GHz router, its performance compares favorably with midrange gigabit models such as the Linksys Wireless-N Gigabit Router WRT310N and the Netgear RangeMax Next Wireless-N Gigabit Router WNR3500.
Though it has just one USB 2.0 port for both drive and printer sharing, you can hook up a hub to attach several different printers and drives. On multifunction printers, however, we could only print (not scan or fax). The AirPort Extreme has three LAN ethernet ports; most other routers have four.
You can format drives in Windows FAT32 or in Mac file systems, and you can back up Macs with OS 10.5's Time Machine. Updates are available through Apple Software Update.
As a 5-GHz router, the Apple beats the Linksys Dual-Band in long-range performance, but it lacks several of the Linksys' significant features--notably UPnP, DDNS, and URL/keyword content filtering. Apple views its own Bonjour network service discovery protocol (formerly called Rendezvous) as a substitute for UPnP, but fewer network peripherals support Bonjour than support UPnP.
The AirPort Extreme does support IPv6, the next-generation routing system intended to deal with the anticipated scarcity of discrete IPv4 addresses and to simplify the de�sign of large networks. This feature is unlikely to benefit most home users, however, since IPv4 legacy support will continue for the foreseeable future.
Setup requires Windows or Mac software (there's no Web interface). But Apple's software simplifies the task of turning the AirPort into an access point.