I have both, but prefer the 272 lately simply because the fit ....Ety with triples = physical torture.
Both are fantastic sounding by the way.
I received my RE400's recently but have not had a lot of time with them. I see Hifiman are going to have issues as usual with their cables,
Just by looking at them.
Now detachable cables should be the go with them because its obvious their cables are their Achilles heel.