ICN-LAS or the reverse on KE
 

Anyone have experience with the direct ICN-LAS or the reverse on KE? How is KE's J?

don't have experience on ICN-LAS, but I have one on LAX-ICN-LAX and SEA-ICN-SEA on KE. Comparing with DL both J and Y are much better on KE.
The only comparable DL product I saw was DTW-ICN and LAX-SYD both on 777.

I personally prefer ICN-SEA - it's not so crowded even in Y and almost 2 hours less in that metal tube.

Flew LAX-ICN several times in KE j and I really like it. I give a slight edge to KE over DL for the J service.

I, too, can't speak specifically to ICN-LAS, but click here http://http://www.flyertalk.com/forum/delta-skymiles/1198446-korean-air-totally-blew-my-mind.html for my experience on a recent flight from JFK-ICN.

In a nutshell, the service is excellent. Not all routes fly the same seats, but on KAL's website you can see which seats are operated on which routes.