Also what hasn't been mentioned is Sky's use of a very conservative 7dB noise margin where BT use 6 and DLM can drop it to 3 which can have a significant difference in synch speeds.
On the other hand, there are many cases where DLM goes wrong leaving people with absurdly low connection speeds. You will see many horror stories here and on the of this happening. The differences between sync speeds for 3 or 7db noise margins are significant and can easily be seen in speed tests, but are probably not much noticed in real life. However, the differences where DLM goes wrong have much larger impact, often leaving people with speeds well below ADSL2 speeds.
Moved (with trepidation) to BT Infinity 2 for upload speed. Happy BE user for several years.
Edited by StephenTodd (Fri 29-Jun-12 15:15:25)