Not for the beginner
Pretty neat, but I'd say *only* if you're interested in the language. As has been said before, there is no kanji-lookup, but it should also be said that you can only get the pronounciations of the Japanese words if you actually search in Japanese; ie. you won't be able to look up an English word and get the Japanese word with pronounciation.

The handwriting recognition can be a bit off at times, I've often had to delete and redraw to make it recognize it properly.

This isn't aimed at the English-language audience, but at the Japanese-language audience. I would recommend that you have studied at least a year before you can have any real use of this.

Fast but with definite problems
Fast, much faster than a regular electronic dictionary. Touch pen/kana selection process makes this very simple and easy. However, as a previous reviewer mentioned, there is no Kanji support. You know it or you don't. The other issue is the surprising lack of even older idioms/slang terms. Definitely not useful if you're a beginner trying to use this in conversational Japanese.

tanciet is wrong
There is no Kanji support. Only hiragana and Katakana

Multi-functional!
This dictionary is great in all aspects. Especially if you need a travel dictionary, or just want to learn more kanji.

A lot of the extra features, such as a world time map (Type in the name of the place, and it'll tell you what time it is there) the chatroom ability that the dictionary can be mounted into.

It has a couple different dictionaries to choose from, and you can choose whether to show just main words, certain uses of the word, or even famous places/slang. They even have entries for 'blog' and 'S.O.B.' in there. Things I don't think you'd find in any paper Japanese/English dictionary!

There is also a great study guide, for learning Kanji, though until you've got a good grasp of the language, that section is overall probably incredibly challenging.

You can put footnotes in entries, and put those footnotes in one of three sections for quick reference later. Truly does everything you'd need a dictionary to do, but faster!

Most words have an English definition, and a Japanese one with both the kanji (if applicable) and the hiragana.

The only trick to it is, if you're trying to handwrite the hiragana/katakana in, you have to make sure to use the proper brush stroke order. Though I do find it fun to make smiley faces and have them turn into different kana depending on the order I draw the face...lol

You can adjust font size, set an alarm, a timer, type in English AND Japanese, and if you're bored, you've got a 50 page flipbook you can draw something in! This is a great material for anyone with a DS and studying/wanting Japanese!