LHR-SFO - planes dilemma

Hey all,
I plan on flying from LHR to SFO on Feb 3rd and I've noticed that on that day the flight is with Airbus 340. The next day both flights are on the 787. I will be flying 'Coach Delight'.
I don't have a completely strict itinerary but I was planning on flying on the 3rd. Is it worth postponing the trip for 1 day so I can take the newer aircraft? How big of a different will it be on coach delight?

I haven't flown in either of those, I was kinda interested in flying with the dreamliner but perhaps it doesn't matter that much for coach?

Thanks!

The seats on the 340 are wider than on the 787.

If there’s two of you, you can get a pair of seats on the 340 with its 2-4-2 configuration whereas the 787 is all 3-3-3 so I suppose it depends how many are in your party?

IFE is touchscreen and much better on the 787

The seats on the 340 are wider than on the 787.

If there’s two of you, you can get a pair of seats on the 340 with its 2-4-2 configuration whereas the 787 is all 3-3-3 so I suppose it depends how many are in your party?

Thanks for the reply.

Its just me, which puts more emphasis on the IFE I guess.