From what I recall, the Octopus card works wonderfully well in Hong Kong - but I was singularly unimpressed with the TfL Oyster card when I considered using it.

The latter lacks (or lacked, in case they have woken up to themselves since I looked at it) one vital component - an incentive to use it.

In Hong Kong, New York, and most other systems I have used, prepayment got you some form of discount - usually at least 10%.

The use of the Oyster card, on the other hand, would have cost me money, because it precludes the use of off-peak tickets and single trips were a lot more expensive than with the carnet, and much worse than a season ticket.

The London Underground person I spoke to about it agreed that Octopus wasn't really very good value, and only worth considering if you were a commuter that travelled only during peak hour but not regularly enough to buy a season ticket.

I don't so much mind if there are no discounts, but to work for me it would have to at least always provide me with the lowest fare that would be available to a cash paying traveller for the same trip. And that was manifestly not the case.

So for now I am sticking with using credit card to buy ten trip carnets from the vending machine.

I wonder if there is any significance to the names. Octopus creates an image of something flexible with tentacles everywhere, whereas an Oyster tends to be rigid and rather closed.

Regards,
DigbyT