just finished a 5 night stay at the grand hilton seoul.
as someone commented above, gold status gets you upgraded from a "deluxe" room to a "superior" room, which has no lounge access. my family got in late the first night so there were no superior rooms available and we ended up in the deluxe. frankly, i felt the deluxe room was better: the toilet/bath are separated from the sink area, and the furniture was more traditional. the superior room has "modern" looking white & black furniture, and the drawers don't actually fit well. also, the bathroom is separated from the rest of the room by frosted glass, not walls, so if someone has to go in the middle of the night, the entire room gets lit up. and the desk in the superior room is not separate from the drawers and TV stand, meaning that you can't sit at the desk and watch TV at the same time.
for both rooms, we took two "twin" beds, but they are really more like american "full" size beds, and each can comfortably sleep two people. the rooms can fit one additional rollaway bed (for about US$50), but we found we didn't need it because our kids are small. i imagine that kids over 10 will want separate beds.
the hotel itself is somewhat remote, but there is a free shuttle that can take you to hongje subway station nearby, or to itaewon. they'll even drop you off at the incheon limo bus stop on the street in front of the hotel (otherwise it's a steep walk downhill).
one major disappointment was the complete absence of wireless. each room has wired internet, but for this trip i didn't want to be encumbered by my laptop so i brought an ipad instead.