What features from a typical wireless router is Airport Extreme missing?
Have you seen the Technical Specifications for AirPort Extreme, that should cover most of the questions. There are no virtual servers and no DMZ, but IPv6, Port Mapping, Shared Disk/Over-the-Air-Time-Machine-Backup, Shared Printers, DHCP and NAT, some features are Mac-only, of course. Wireless 802.11n with various transmit power options. That's about it. As I said, no toy, but it works 100% reliable, even for techies.