KCS is a very traditional school. I should say if you are looking for fancy campus, nice artworks to bring home, etc, KCS cannot provide you with such. But KCS did provide a very good language environment for my kid. We never speak any mandarin with her, but she can sing a lot now (and we have to keep guessing what the words are about!) and also mandarin 三字經 -- of course that's just another song to her.
KCIS is my number one choice and i will be interviewed on 24/11. Please note that N students are not guaranteed to any admission to both stream of K, they just have priority in the line. KCIS is getting more and more popular these days as it is so strong in Chinese. But of course, its campus, the location, the traffic around, is nothing compares to other IS.