Or if you have the cash, NTC's New Japanese-English Character Dictionary (same people that make KKLD).

Question, how does Kodansha's Essential Kanji Dictionary differ from the Kodansha's Kanji Kanji Learner's Dictionary?

From my own experience Japanese-English character dictionaries are only of use while doing RtK (specifically getting a sense of the keyword's actual meaning).  I have both KKLD and NJECD, and while they excel at this purpose and I would recommend purchasing them just for that, I have not once found them useful for anything else.

I'm not familiar with the Essential Kanji Dictionary, however.

The New Nelson Dictionary is the best one to get in my view.

There is a review of the major dictionaries that's quite useful.

Note the link in that review to a feature comparison chart.