It's better because:
1. There are lots of computers with internet and 18" LCD monitors

those monitors cost more than USD 2000 each!
2. Seating is a lot more comfortable
3. They have lockers to lock your bags and etc. away
4. Well, no need to mention anything about the food (and drinks)!!

and 5. Personal preference, but the decor is a lot more relaxing IMO
But UA's NRT lounge is better in terms of the showers: I love those showers!
And I guess the First Class section of NRT is better than ICN's Silver Kris (ICN Silver Kris = no difference between F and C class lounges apart from the material of the chairs... even the food is the same)