i stay in singapore and have visited south korea before. and this is just my opinion.
food: i may be biased, but i would say singapore. there are plenty of variety of tastes because of the mix of cultures in singapore. but if you like korean food, obviously s.korea is the place to find authentic korean cuisines.
hospitality: about the same. debatable. depending on where you go, who you meet. you will get good experiences in both countries and also equally poor ones when you are not lucky.
clothes: possibly s.korea. the styles are trendier (esp. for young people). but their cut tends to favour those who are slimmer. singapore shopping though, is not bad too.
beautiful: s.korea is a much larger country than singapore. if you have the time to visit many places in s.korea, then without question, s.korea has more to offer in terms of beauty of the places. if you are limited in time and is spending time in only a major city, i would think it is debate able which city is more beautiful.
ease of getting around: singapore. partly because english is widely used in everyday communications.
weather: singapore is hot and humid, so may be uncomfortable to some. s.korea has 4 seasons.. so depending on when you go, the weather can be pretty nice.