I get a very stable 8Meg connection with Eclipse
and my nextdoor neighbour gets an unstable 1Meg connection from BT
Maybe your neighbour is an idiot then, BT are only responsible up until the master socket. Are you saying that Eclipse magically replaced all the cabling to your house.. err no they use exactly the same BT infrastructure!
If your neighbour does some rubbish DIY phoneline extension that causes so much noise on the line that ADSL can only work at a low rate, you cant blame BT for that!
Start by disconnecting the extensions, and replace any worn out phone wire and ensure its terminated correctly. Use google for research and remove the extra bell wires that you dont need to reduce noise (30second job) and then replace the 50p face plate with a decent quality one (£10-15) Hey presto, cometh the superhighway!
I like to kick BT as much as the next man, but you have to get your own house in order first! If you pick up the handset and can hear noise on it, how exactly do you expect ADSL to work fast on it??? Do the checks, make sure your wiring is in order, then report it if its still a problem and BT will come out and fix it!