Except for the usual differences that apply to all subtags (such as parsing order), these are more or less equivalent for an array-type list:
[accessories code=current_item_code arg=arglist] [item-accessories arglist]
See the [accessories] tag for more detail. Note that you must use the comma-delimited list to set attributes -- you cannot set named attributes with the usual 'attribute=value' syntax.
If the list is a hash list, i.e. an [item-list], then the value of the current item hash is passed so that a value default can be established.