I've had the AEBS since June. Overall I'm happy with it, but it is not without its flaws.
Range: Seems fine, I don't have a big house, and I have an APEX extending the network anyway, but haven't had any problems.
Internet: No problems, I have AT&T DSL. I haven't had any dropped connections.
Printer Sharing: No problems with a HPLJ 1200 (powered USB hub)
Airport disk: Working with a 500GB Lacie Porsche USB only drive (through a powered USB hub) This is a firmware issue that has not been fixed. This feature is not implemented properly yet. I can report with firmware version 7.1.1 that the disk works fine with the only caveat being the drive has to be powered on before the AEBS is powered on. Many drives do not spin down, and most that do, do not spin back up when accessed. Otherwise the airport disk has worked fine. 2-4MB/sec read/write over a 802.11g network. Slow, but manageable enough to use as an iTunes music server.
If you read on Apple discussion forums, many people have trouble with the newest firmware 7.2.1, myself included. When I switched back to 7.1.1 it works as long as I power the hard drive up first. Some have had some success with turning DHCP off or turning the lease time way up.
I don't think the read/write speed will get any faster. The processor on the AEBS, and most routers, is not powerful enough. If you need faster file serving, an old PC or mac mini would be best.
Other items: There is a space for Wide-Area Bonjour, but it does not work. In order to access your attached hard drive over the Internet, you need the IP address (or have a computer running a Dyndns client). Port forwarding is fine, although every setting you have to reboot the router.
It's an easy setup, a little pricey, but I'm happy with it