Is it better to have Tzitzis made from cotton if the garment is made from cotton?

Question

I recently saw in the Mishna Brura that wool or linen Tzitzis strings exempt 4 cornered garment regardless of what material it is made of, however strings made from the same material as the garment will permit it as well, but not another garment made from a different material (i.e. Cotton strings will only exempt a Cotton 4 cornered garment not a any other material). That being said, is it better to have cotton strings on a cotton garment or Wool/linen?

Note: This is ignoring the later halacha in the Shulchan Aruch where the MeChaber cautions against using linen tzitzis strings/Garments. It is a question on weather B'mino is more ideal than wool/linen tzitzis- which exempt all 4 cornered garments regardless of their material.

Answer 1

The Alter Rebbe poskined in Shulchan Aruch HaRav that the primary thing is to be of the same species. This is discussed in Shulchan Aruch HaRav, Orach Chaim, 9:1-4, 11:10.

http://hebrewbooks.org/pdfpager.aspx?req=25072&st=&pgnum=70

http://hebrewbooks.org/pdfpager.aspx?req=25072&st=&pgnum=79

It's worth noting that he points out the concept that wool and linen fulfills for all garments seems to be only when techelet is available. He also brings the view of Rabbi Meir of Rotenburg that this may only be applicable if two of the tzitzit are wool and two linen. He also relates this idea that according to some, garments of species other than wool or linen are not obligated for tzitzit at all. And so, in that context, he holds it is preferable that the tzitzit be the same species as the garment.

So the running emphasis is that the more stringent idea is to have the tzitzit the same species as the garment.

He also suggests the most preferable choice is that the garment and tzitzit be only wool and that this covers all possibilities.

But today, at least according to some, we now have techelet available. And this opens up all the alternative options which the Alter Rebbe outlines.