First open VoIP router? Hardly.
The SPA-2100 has a fairly standard NAT firewall/router combination with QoS grafted onto its voice capabilities that are similar to a SPA-2000, i.e. two independent FXS ports. The router is a firewall which does NAT and supports static DHCP reservations, port mapping, PPPoE, Mac Cloning on the WAN interface and DMZ mode. These features are found in many residential-grade routers.
The SPA-2100 only has two ethernet ports: a LAN and a WAN port. They are auto-sensing, which basically means you don’t need to worry about if you need a crossover cable or not. However, the SPA-2100 does not include a switch, which I presume the D-Link box does. Depending on your starting point in the home networking process, this might make the SPA-2100 more expensive since you will need to acquire a seperate switch.
Now, granted, you cannot go out and buy a SPA-2100 in stores–yet. You can buy a SPA-2100 from Voxilla where you get a free month of BroadVoice and 100 minutes on iConnectHere, but it wouldn’t surprise me if you saw the SPA-2100 in a retail package from BroadVoice at some point in the future.