As BA was mentioned by OP this might be worth comparing your experience to.

The brother and wife decided to treat themselves for their 10th anniversary. BA via LHR to LAS in J. Booked via a travel agent.

For reasons that were never fully explained DUB-LHR was on a separate ref to the rest of the itinerary. So they had to collect bags at LHR and recheck to LAS. They did this.

As noted in an earlier post BA charge for selecting J seats. Cost them 160 sterling to choose seats on outbound and return so they could sit beside each other. Also had to pay for WiFi. As noted EI don't charge for either.

Their bags didn't arrive with them. This was Friday night. They didn't arrive Saturday. They didn't arrive Sunday. They didn't arrive Monday.

They DID arrive Tuesday. On the plane that was to take them home.

A nice Swissport chap at LAS told them he would personally see to it that their bags were turned around immediately and sent with them back to DUB.

They landed in DUB half an hour ago. No bags.

And on top of that, when they arrived in LHR this afternoon, having flown J class out and back to London, they were refused use of the BA lounge because their flight to DUB was in Y.

I'll take EI every day of the week ahead of that kind of experience