On BA you can upgrade from WT (the economy class) to WT+ (World Traveller Plus, BA's premium economy class) for USD 300 when flying from London to Brazil. Otherwise segment upgrades are not permited on One World Explorer fare.

IB doesn't have a premium economy product.

Your elite status won't probably make any difference on board. BA and IB will first see that their own elite status passengers are accomodated IF there's a need to do operational upgrades.

Anyway, based on what I have been reading (no own experience on long-haul IB) I would choose BA.

[This message has been edited by JuPe (edited Dec 29, 2003).]