I don't disagree that the more an attacment is designed for a purpose, the better it can be for that. But bucket grapples are very useful. It also allows for material removal that you want to get rid of which would/might sift through a grapple bucket. I guess it depends what you want and what you're willing to put up with.
In my use, I could not justify a dedicated grapple and elected to go with the bucket add on grapple. The real advantage of a true grapple bucket (to me) was moving big logs that stuck out the end, carrying them closer to the pivots. I did not really need that since my fel has 2,500lb capacity. As far as brush goes, or dead stuff, my grapple add on crushes the brush into my bucket anyway, so the sides do not become compomising at that point. The bucket is a great help for me instead of the sift feature, as I move a lot of crud, broken branches, rocks along with the brush piles. If this stuff filtered through, I'd have to put a bucket on and pick it up afterwords in my case.
Just another view on the subject.
Here are some pictures of my bucket add on grapple in use.
To put it in perspective, my 55hp Kama is pretty big pushing 7,500lbs loaded.
This is one before the add on grapple with only a toothbar. So it all depends on what you want to do and what you expect.
