We just completed a multi city itinerary - BOM/DXB/ZAG and MUC/DXB/BOM in J. Two of the four legs were on the A380. However, the flight we enjoyed the most was DXB-ZAG which was on the reconfigured 777-200LR. I'll highlight what we liked:

1) J has got a 2-2-2 config which is super spacious. The aisles felt much broader than on the A380 and one design decision they have made is to take out the overhead bins in the middle section. In fairness, Emirates has nicely designed bins and they don't feel intrusive on the A380, but taking them out here just made the cabin feel very airy and spacious. You just had the sensation of space all around you. By comparison, the A380 felt more coffin-ey. I do wonder though if the lack of middle overhead space might be an issue when J is full. Our flight had only 40% seats taken in J, so it wasn't a problem, clearly.

2) The new seats are AWESOME! They are nice and broad at about 22.5 inches, and it's funny that just a few inches should so greatly add to your comfort. The seats are firm and nicely padded and the new diamond quilt stitching is very good looking. On the A380, I have always felt the seats are good if you are a back sleeper and don't move much, but if you're a side/tummy sleeper who turns a lot, these seats are perfect. I honestly slept the best on this flight that I can remember. The screens are massive and sharper than the A380. The wood veneer used is darker than the blond wood veneer on the A380 and looks very classy.

3) These seats are the best for families. In previous Emirates flights, I was flying solo and I guess I had appreciated the privacy on the A380. But when you're with your family, it's hard. On the first A380 flight, my mom and I had single seats behind each other and it was impossible to communicate without one of us getting up. On the second A380 leg, we switched to one of the middle 2's, but didnt find it much better. On the 777-200LR leg, we just had to lean forward a bit to chat (for solo travelers, you can pull forward the large privacy screen, no issues).

In conclusion, I think Emirates did a great job with the reconfigured aircraft. Kinda wish all their aircraft were similarly outfitted! BTW, I peeked into Y, and that looked pretty good too.