Yes, I have flown DFW-ICN twice in business.
Thought it was very nice. Seats are not the best, but if you are a SkyTeam elite, I "asked" for seating in the F section and it was given to me (only asked the 2nd time!). They have "first" but only sell J and Y.
Food was OK, infact, they did a nice noodle dish on request which was very tasty.
Business class was about 50% full so you could spread out.
I was pleasantly surprised! Enjoyed it more than the LAX-ICN on the 747.