They're not bad and deserve some praise, but equally I've seen other companies do better.

For some reason, large companies have never taken email seriously for CS - most say they'll get back within 48 hours and I've never understood why email isn't manned like Twitter is, with responses asap. It works well as both parties can respond when convenient, without either being inconvenienced, unlike phone calls with their huge queues - but sadly companies don't see it as a means of engaging with customers.

Twitter is generally good for the customer, however I do feel sorry for those manning it on behalf of BA etc. It is such an instant vent that people say the most horrific things on there which most would never dream of saying in person - it must be quite depressing being 'shouted at' all day. Unfortunately the way of the world is that everyone expects everything instantly, and if that doesn't happen, stress levels rise and people kick off.