Heathrow has had something of a major transformation over the past few years. 5 years ago you could expect long queues art check-in longer queues at security more long queues at immigration and extensive waits for your baggage - if it turned up at all. The terminals were drab and outdated - threadbare grey carpets cheap red plastic old fashioned information screens. In my experience this isn't the picture anymore. Check-in is mainly down to the airlines but certainly for BA the queuing has all but gone for United - not so much. Security never seems to take more than 5 to 10 minutes - same for immigration. As for baggage the last couple of times - it's beat me to the carousel and the time before that it was only a few minutes. The terminals themselves have been updated and Terminals 1 and 4 are now bright clean and airy. Terminal 3 is brighter but still feels a bit cramped. Terminal 5 which is new is excellent. I'm sure people still occasionally still have bad experiences and I've never changed flights there. But for me Heathrow is no longer somewhere I try to avoid.