In between Hong Kong's Octopus Card and the United Kingdom's Oyster Card, which one is better?

I know that HK's Octopus Card can be used in a lot of places (mostly because I live in HK) like the MTR Train System, Buses, Resturants, 7-11's, Supermarkets and to confirm identification at schools and office buildings. But because I've never tried the UK's Oyster Card, I want to know which one is better. And which one launched first?