OntimeexceptACARS - If you're going to the USA, the best option IMHO is to go via Ireland and do US immigration control before boarding at DUB or SNN. It will save yours hours of uncomfortable queueing on arrival. As far as onboard comfort is concerned, the Aer Lingus A330 was fine last time I flew it.
The only BA service I would consider would be the LCY morning departure (but no economy, sadly).