Just wanted to post yet another reason why RTK is so useful:
I've recently made a few Chinese friends at my school purely through knowing RTK and being able to competently read Japanese material.
I can speak one word of Mandarin (albeit badly), Nihao. Yet, knowing the 2042 Kanji, plus some various 100 or so from book 3, I found mutual ground with a few Chinese students in my classes at school, and through discussions on the English meaning of various Kanji, we've become friends. One of them was particularly impressed when I read the Heisig keywords that made up their name. So, although I know practically no Chinese, no simplified characters, but I know RTK, I've bridged a language gap (just a little bit) rarely crossed by western high school students.
I will learn Chinese using RTH (Trad. and simpl.) sometime next year, but not for now.
I've recently made a few Chinese friends at my school purely through knowing RTK and being able to competently read Japanese material.
I can speak one word of Mandarin (albeit badly), Nihao. Yet, knowing the 2042 Kanji, plus some various 100 or so from book 3, I found mutual ground with a few Chinese students in my classes at school, and through discussions on the English meaning of various Kanji, we've become friends. One of them was particularly impressed when I read the Heisig keywords that made up their name. So, although I know practically no Chinese, no simplified characters, but I know RTK, I've bridged a language gap (just a little bit) rarely crossed by western high school students.
I will learn Chinese using RTH (Trad. and simpl.) sometime next year, but not for now.

I'm only half way through, but it's awesome actually seeing them in real life.