>Changing between terminals at Heathrow is much less fun.

I decided to stay at a Heathrow airport hotel a while back. Turned out I had to change terminals and I'm pretty sure it took me at least as long as getting a shuttle bus to one of the hotels would have taken.

You often have to walk quite a ways too.

Overall though Heathrow is pretty good among the large European airports.

I actually kinda enjoy the distance between terminals. After a long international flight, I deliberately take the tunnel, and skip the moving walkways. As long as I'm not rushing to make a connection, the walk is really nice.

Except for the incredibly low ceilings in some places.

I would argue that's the only nice airport in Scandinavia even! Would say the worst layout on an airport i've ever seen is Stockholm Arlanda.