I rarely bother to write reviews but, for AAISP, I'm willing to make the effort.
Their staff have always been helpful and knowledgeable and service is spot-on. I've recently upgraded to FTTC from ADSL and am regretting not spending the extra tenner a month sooner. From 4Mbit if I was lucky (long line) to maxing out the 70Mbit sync speed I now enjoy!
I have now asked them to take over my phone line so that I can finally ditch BT retail.
Other services such as VoIP are also excellent. Line monitoring helps for the odd hiccup and their control panel allows for all the tweaking you could reasonably expect, plus a bit more!