Just finished a two leg flight in J: MRU - DXB on A380 and DXB - BOS on a 777.
The A380 seat width is noticeably more narrow but with the minibar thing next to you it felt like there was more elbow room. Also the seat gets closer to 180 than the 777.
The 380s are overall a better flying experience but service can be a little spott(too many seats not enough staff).
Would say the service on the 777 has been fantastic.