OK, here's the honest truth. The only real reason to buy the Airport over other routers is the USB slot for a hard drive and/or printer. Or if you buy multiple airports to cover a larger area.
But if you are planning on plugging in a USB hard drive to your airport, you better be ready to unplug it, plug it into your mac, eject it from your mac, and plug it back into the router pretty much every time you want to use it. This is a known problem with the AEBS. Also... intermittent drop outs are common, so be prepared to restart your router once in a while.
When Apple gets these problems fixed, the AEBS will be amazing. But the truth is, right now it is annoying. It is expensive and it doesn't do what merit's it being so expensive... at least nor properly or smoothly.