Contention is quoted as 20:1, but you would never expect to actually receive only 1/20 of the service you pay for.

As an example, ZEN state that they provision for 100% of their customers bandwidth. That's how they can sustain high speeds.

OK, when tings are busier, contention will be a factor, not it's not affecting anyone on ADSL yet.

With only 1Mb leased line backhaul, you will get unhappy customers.