Actually, having had a second go at the CX lounge early in the morning, I have to say the service is very good. So I'll revise my opinion: unless you want very fast food or to fetch your drinks yourself and not talk to anyone, go to CX. BA has faster food (from the buffet) and self service drinks.

The CX service is friendly and extremely attentive. The food is overall good, although the omelettes can be a bit greasy. If you want a decent portion of yoghurt with the "healthy start", ask for it - the standard portion is more of a garnish of yoghurt for the granola

One can easily get a full breakfast in half an hour.