They're harmless enough, that's what I get going LHR-FRA-LHR routinely.
I'd prefer it if the seats could not be reclined for hops like that as I have long legs and I dislike slouching.
I reserve some affection for DC-10s as they were the first LH aircraft on which I travelled.
I can't say I've ever been on an airliner I did not like in some way.