I recently visited both the Asiana lounge and Singapore lounge and ICN and the Singapore lounge had a much, much more varied food selection but I didn't necessarily think that the quality was that much better than Asiana's. Also greatly prefer Asiana's self-serve alcohol situation. Singapore's lounge right now also has restrictive hours (seems to be only open for a few periods of a few hours each period each day and, on the day I was traveling, the entire bathroom was out of order and roped off and they directed people to use the toilets in the terminal.