Just recently redid my network because of the modem comcast gives me has a built in switch/router and I have a large area to cover, put in a couple netgear switches and was about to get a high end netgear AP, but then decided to go with the Airport Extreme. The Airport Extreme was about 100 bucks cheaper, and I like it a lot, It covers My entire house, three stories, and my brothers house too (which happens to be the house right next to mine). I never really thought these could possibly be worth the money... ...until I owned one. I'd say it's totally worth the extra 50-80 bucks for this.
No down time or anything, extremely fast and handles high volumes of bandwidth, internet and local, and extremely easy setup too. Another nice thing is you can plug external hard drives into it, which makes wireless time machine backups and I have frequent backups now. Also acts as a NAS for other files.