I do this 4 or 5 times yearly.
Being SEN gets you nothing.
It's better than LH/LX. More food and better quality. And you don't have a hub to get to.

You'll get a 777 with 2-3-2,normally 4 rows with toilets at back on each side. PTV.
Occasionally you get AVOD, which has 5 rows, and also has a coffee bar affair up front behind the partition.
Food: served and gone by 11 pm will be fish plus salad; restaurant sized main course; cheese fruit dessert (all of that). Choice is steak or fish usually, with Korean alternative. Wine you choose with the choice of meal at the start. Water bottle for flight and crew walking up and down all the time to see if anyone needs anything.
Mid flight you get noodles, if you want. 3 hours before landing (lunchtime in Korea, but about 4 am in your head) you get a two course lunch, often beef kebab or saithe.

PTV is pretty disastrous, as it often doesn't have what is advertised on it in the way of films. I saw Wizard of Oz a month ago, as best choice.........
Seats are good, lie flat at 160 degrees. Arm goes up and down as you recline or not.
Crew are excellent.
On way back you get 3 meals, and probably a face-pack (really!)