In life, I feel you get what you pay for. I've been with AAISP now since January when I moved into a house with FTTC, having also used them for ADSL about 2 years ago. I've always been incredibly impressed by their impeccable service.

In the first flat I had a complicated installation due to antique wiring and BT being a real pain, AAISP sorted me out - offering me a SIM card / cellular solution until I got the line installed (I didn't need one as I had one already, but the offer was noted and appreciated!).

In the new flat, I was able to use my line via ADSL - again due to competent, technically savvy support staff - before I got my fibre line installed, and their support after that has been impeccable.

AAISP are by far the cheapest ISP, but as a customer I feel that thier costs really do reflect the service you get from them; real support staff with real knowledge - no scripting or overseas support centres, combined with uncontended, unfiltered internet lines with lots of control for you to get the most out of your line (i.e. throttling to ensure VoIP quality of service, etc, all comes as standard configuration settings).