The rear end - the No 2 engine installation - always looked unfinished, and done in a hurry on the DC, whereas the Tristar looked much more complete.
The Tristar however only had overhead lockers on the outside: none in the centre, so there was always a fight for them, as there were too few for the numbers on board. (A bit like the lifeboats on the Titanic I suppose).
But then an experienced engineer told me that long dark nights in the hangar maintaining Tristars were enlivened, on occasion of removing the centre engine, by placing a mattress on the hangar floor and using the engine intake as a rudimentary helter-skelter.
I quite went off it after that.