Well, I was quite surprised. I did a couple of price checks on flights ex Bangkok, one a standard intra asia flight the other an AA flight to SJC using JAL as a codeshare on the BKK-NRT portion, which I know previously has been for sale at a substantial discount over the regular J fare. The prices that came back were very close to what I am quoted by discount travel agents in BKK. I guess it all depends on where your travel is originating from. It is quite possible that in the markets where oneworld has a substantial presence the system will not offer the special net fares that are usually available through a travel agent.