At the Amex, I listen via the FM Radio app on the phone, so it is real time (I guess a fraction of a second delay) which is easiest to determine before the match starts when they are doing things like interviews on the pitch. I find it really useful as Warren and JC are on the half-way line, so...
I often listen to the commentary via one earphone at the Amex. Also helps with finding out about other scores which may affect/amuse us, plus more importantly helps with understanding incidents that are hard to make out from where you're sat.