Which MBBR carier model is the best?

Hello Dear technical fellows.

I'm making a research job about MBBR carriers models. Seeing that they are to many in the market, I should ask you: Which one is the best? what is the characteristics that they have to have, for example:

Specific Area per Volume of carries (m²/m³);
Maximum size of the holes inside de carrier (mm);
Total volume of the carrier (piece);
Which ones are patented and who are their owners (of the process)?

My intention is to develop a different model to my on use, And I would like to hear from you the best characteristic that those carriers must have to be a good one. I'm already with Metcalf & Eddy reference about, but it brings only a few information about it.

Thank you very much for your help and kindness. I'll look forward for your comments.
Best, Léo.