Is that a 767-300 (763) or 767-400 (764) with DL? The reason I ask is because we are flying ATL to DUB in August and it is currently scheduled as a 764. If it is a 764 it will definitely be updated as these planes were reconfigured to BE cabins within the last year or two. We've been on several and they are very nice. Firm leather seats, a good amount of recline, AVOD, 60 inches of pitch. If a 763, it most likely will be updated, but not a 100% guarantee. Even if not, you still have in-seat video, the recline is roughly the same but the legrests don't come up quite as far (making the recline functionally a little less).

We've flown CO 757s back/forth between EWR to ARN and found them quite comfortable too. One thing we liked was the smaller BE cabin had a quieter feel, not that the DL two aisle ones are noisy. The pitch is about five inches less than on DL (55 CO v 60 DL), but the seats are wider (20 CO v 18.5 DL)--if either of those is a significant factor for you. The food was definitely better on the CO flights, but we ordered special meals (Hindu Vegetarian) on the CO flights. Delta's special meals are bleak, and we have to hope the pasta serving isn't some artery clogging cheesy something or other in a cream sauce. The service is usually good with both DL and CO.

Living in ATL, I wouldn't find enough difference not to fly DL on a route where I could get a non-stop flight TATL. I assume you would be coming from southern Florida and would have to connect somewhere or other anyway. If that were the case, I'd go with the best connection. If you can get either as a non-stop, that is the way I would go.