I don't think any companies are accepting new people for the 80/20 trial as its due to end quite soon, I am sure Aquiss will offer the 80/20 product though as soon as its available which is from the 10th April if my memory serves me correctly.
I was with Aquiss myself for ADSL for a number of years and then their business FTTC product for the last year. On the whole it was a good experience and fantastic tech support form Martin for the odd issues that did crop up.
I swapped to BT Infinity in Feb after a few issues with very slow (sub 1Mbps) download speeds with Aquiss during some busy net times (Andy Murray playing tennis in Australia and everyone with an Entanet connection seemed to be watching it on the web) and also to save some money.
I would like to tell you what a horror story its been with BT but tbh after getting past the farce of the initial install (they said I needed an engineer visit even though I was moving from one FTTC product to another, but then he didn't show when the appointment was booked anyway, didnt matter though as changing settings got me connected) its been very very good.
Its very painful speaking to their tech support in India and if you value customer service highly then Aquiss is definitely the place to be but overall I am very happy with my change so far, the cost savings and there's been very little slow down even at peak times.
I am sure this thread will come back to haunt me one day though ... my past history with BT tells me that's inevitable!