Never trust sales personal from isp's I have had plenty of laughable claims from the voices of the sold end user ie ' The line is about 8kms rural we can give you 2 meg' . On the fault my exfo 'next gen tester' passed the line as decent not 100% but no ambers or 50/50s.
I did achieve sync @ 300kpbs or so 6db down interleaved, with the end users hub not doing much apart from flashing orange this being normal as the tester will sync better than most routers.
If i coiled up 8km of cable and tested from the exchange then I may get the 2 meg it would be a fun experiment.
What people have to understand that sales staff dont have a clue, just want the sale, customer service first line dont have a clue either! sometimes I need to deal with them Hello my name is xxx from xxx isp, I then introduce myself and who I represent, they reply ok have you tried this in the test socket
when im actually in the exchange. They both run on scripts and what you want to here calculations.
The best advice is different ISP's will be better than others in different areas. The biggest mistake the end user can make is compare to a friends service from isp A they stay in another exchange area and different line distance.
So between them on a quality pair the difference will be in the small print and price + benefits.
Hope that helps