As other comments note here, this isn't the cheapest ISP, but what they offer to those of us who like tinkering is invaluable.

Where else can you get a static IPv4 address, a /48 block of IPv6, no traffic shaping or filtering and constant quality monitoring with the base package? I can log into my control panel and get a clear graph of whether anything is wrong with my connection, change line parameters, issue line tests or get a description of the communication going on between AA and the line provider (BT, in my case).

I've also ran a few tests on the connection and measured latency and DNS resolution times, two very important metrics that are often ignored. I was happy to find out that the latencies were some of the lowest I've seen, and DNS resolution is even faster than Google's public DNS. Bandwidth is of course maxed out on my ADSL line (as in, the connection is as fast as the line allows).

I suspect that a lot of users won't get much benefit from all the tinkering options, but they will still get a great connection and a support staff that actually know what they're doing. As an example, I requested a change in tariffs the other day, and after just a few minutes, not only had the change been made, but retroactively applied to the current month.

I'm very happy to spend some extra money on a fast, stable connection with knowledgeable support staff, and I suspect I'll keep doing so for a long time.