4x4 box with plaster ring vs standerd electrical box?

4x4 box with plaster ring vs standerd electrical box? what do you prefer? i want to use all 4x4 boxes but can not find a ceiling type 4x4 electric box that uses a plaster ring and has a between joist support arm. i like the 4x4 boxes because they can hold lots of slack wire. also what are the pros and cons of the 2 box styles.