This product is of high quality, but it is not simple to configure. And unlike most ADSL/VDSL routers, the software updates are not freely available online. You need to buy a support contract for the software, even while the hardware is still in warranty.

If you need a Cisco router for a small office on an BT 21CN ADSL2+ line I suggest you avoid previous Cisco ISR versions and go for the VA model. For whatever reason it has taken a few attempts to get stable hardware/firmware for these lines - see...