Just checked out the MH website, after all the fanfare of the joining, the update to the website is pathetic!. If you check out the website, they have added the Oneworld logo, but sadly that is so badly aligned it is covering part of their own kite logo.
Checked out their enrich page - just to get a clue on how it would be, no OW airlines are listed there as yet.

Quite a disappointment.

Btw, did anyone catch the whole joining event live on web? Saw a few of it, pity that during the introduction/welcoming greetings from the various airlines, there was a bit of screwup in line up, they mixed up LAN and Japan Airlines.. I think this threw those poor airline representative off course.. some of them got rather nervous.. the S7 rep got lost in words and abruptly ended with her Russian welcome.

Cheers!