EI was a client of mine in the 1990s and I had to fly them all of the time in J. It was not a pleasant experience back then.

I have flown them recently in J and it is just fine but definitely not a "great" experience. Keep in mind that East Coast to DUB is pretty much the shortest TATL flight that you can do so don't expect to sleep much. I only mention this because you may value the food/drink/(lack of)wifi tradeoffs vs DL. rather than the seat on such a short TATL flights.

When I fly TATL these from the East Coast, I try to route through ATL or ORD to get more sleep time.

I flew JFK-MUC in F on LH last month and didn't sleep for a second, which is a shame because the seat was very very comfortable!

There are a lot of good deals to BCN right now. Have you checked out IB?

TFD