I haven't used Remembering the Kanji so I can't compare, though when I did my research on which book to buy I did ultimately settle on Kanji Learner's Course. I believe the difference was RtK didn't have ways of remembering how the kanji is read? Only the meaning of the kanji? KLC gives a TON of information on each kanji and it has different ways of looking them up too. It has some references in the back too, such as kanji used for names.