I upgraded to Mountain Lion last week, which means Dictionary (an app that comes with Mac OS X) comes with Super Daijirin and Wisdom (Sanseidō) instead of Daijisen and Progressive (Shōgakukan). Not really sure what prompted that, but I have a theor¥. I can use the old ones as long as I forget to update things anyway
So for the waei portion, I’m not sure I like this change so far; maybe the layout change is throwing me off, but Wisdom seems to have less example sentences per entry. Progressive tends to have a carefully chosen selection of examples (with varying word choice if appropriate) that really helps jog the translating juices (e.g. when I know the word but am struggling to go beyond simple synonyms). Wisdom seems to explain things better for Japanese speakers, though. Maybe once I stop taking 16-credit semesters I’ll be able to give this one a fair shake, but then some things have changed, because more now than a couple years ago, I consult the dictionary a bit less for word lookup and a bit more for translation assistance.
For the kokugo portion, there isn’t really an appreciable difference for my own purposes, though technically I don’t recall Daijisen telling anything about accent. Sometimes there are words where only one of the two has it, or where one has it hidden as a subentry. I used to go to goo’s or Yahoo’s dictionary sometimes for exactly this reason, but I guess now I don’t have to bother!
Anyway, I’m sure someone has already compared these two more thoroughly.
If I want waei lookup for something that isn’t in the OS X Dictionary, I typically go to WWWJDIC next. Then I go to ALC as the penultimate resort (before hitting up Google). This usually only happens if the word is hella obscure or if I want to really
check a term thoroughly.
One thing that I feel is sorely missing from this transition is 類語例解辞典, which explains (in Japanese) the distinction between certain words that might get confused.
And I don’t really translate the other way around (actually, my Japanese production is pretty bad
), so I don’t have an evaluation of how these dictionaries help there.
The primary motivation for using these dictionaries, of course, is that they’re easy to access (cheap/free/fast/camewithmycomputer).