Mostly I mean the paid add-on dictionaries. In dictionaries, you're getting what you pay for.
The interface to the dictionaries is good, but very straightforward. I don't think there's anything magical about it.
> In fact, the EB apps seem to offer more advanced functionality like dictionary groups and different search types (prefix/suffix/infix/exact/full-text).
Those search types are also available in Pleco, but you have to read the documentation to learn about them. The app has no way of teaching you to use them.
> In my eyes, the best general purpose J<->E dictionary (Kenkyusha [2]) is still better than the best commercial C<->E dictionaries, but it is aimed at Japanese speakers studying English and a bit hard to use for beginner Japanese learners.
I think this is a real issue. The native language of the intended audience has a huge effect on how useful the dictionary is for whom. This really shows up in the E -> C dictionaries available for Pleco, which seem to be targeted at Chinese speakers even when they are paired with C -> E dictionaries intended for English speakers. ABC / ABE is an offender there.
But by way of an example of what having a good dictionary means, here are the CC-CEDICT and ABC entries for 以:
-----
1. to use
2. by means of
3. according to
4. in order to
5. because of
6. at (a certain date or place)
-----
"coverb" [preposition]
1. using; taking - 以合成橡胶代替天然橡胶 use synthetic rubber in place of natural rubber
2. because of - 以盛产红茶著名 famous for abundantly producing black tea
3. in order to; so as to - 以应急需 in order to meet an urgent need
suffix
（"empty" verb suffix) - 加以 add; 给以 give
fixed construction
1. 以 A 为 B: take/regard A as B
2. 以 A 来说: as far as A is concerned
bound form [meanings that the character may express when it is part of another word, but not when it is independent]
from a point on in 以下，以北 [etc.]
-----
In my opinion, if you're using the PLC dictionary, you're not using Pleco correctly. (CC-CEDICT has lower quality entries, but is nevertheless better than PLC because it has entries that can't be found in other dictionaries, such as the Chinese names of foreign celebrities. PLC has OK quality, much better than CC-CEDICT, but if you're looking for entry quality you should use the paid dictionaries, which are quite far ahead of PLC.)
The interface to the dictionaries is good, but very straightforward. I don't think there's anything magical about it.
> In fact, the EB apps seem to offer more advanced functionality like dictionary groups and different search types (prefix/suffix/infix/exact/full-text).
Those search types are also available in Pleco, but you have to read the documentation to learn about them. The app has no way of teaching you to use them.
> In my eyes, the best general purpose J<->E dictionary (Kenkyusha [2]) is still better than the best commercial C<->E dictionaries, but it is aimed at Japanese speakers studying English and a bit hard to use for beginner Japanese learners.
I think this is a real issue. The native language of the intended audience has a huge effect on how useful the dictionary is for whom. This really shows up in the E -> C dictionaries available for Pleco, which seem to be targeted at Chinese speakers even when they are paired with C -> E dictionaries intended for English speakers. ABC / ABE is an offender there.
But by way of an example of what having a good dictionary means, here are the CC-CEDICT and ABC entries for 以:
-----
1. to use
2. by means of
3. according to
4. in order to
5. because of
6. at (a certain date or place)
-----
"coverb" [preposition]
1. using; taking - 以合成橡胶代替天然橡胶 use synthetic rubber in place of natural rubber
2. because of - 以盛产红茶著名 famous for abundantly producing black tea
3. in order to; so as to - 以应急需 in order to meet an urgent need
suffix
（"empty" verb suffix) - 加以 add; 给以 give
fixed construction
1. 以 A 为 B: take/regard A as B
2. 以 A 来说: as far as A is concerned
bound form [meanings that the character may express when it is part of another word, but not when it is independent]
from a point on in 以下，以北 [etc.]
-----
In my opinion, if you're using the PLC dictionary, you're not using Pleco correctly. (CC-CEDICT has lower quality entries, but is nevertheless better than PLC because it has entries that can't be found in other dictionaries, such as the Chinese names of foreign celebrities. PLC has OK quality, much better than CC-CEDICT, but if you're looking for entry quality you should use the paid dictionaries, which are quite far ahead of PLC.)