One thing to remember is different thread for different functions. Also thread comes in different weights for differnt functions. And to further confuse you they are made with different products, cotton, polyester, rayon and silk.
May I suggest you go to
www.superiorthread.com for information and an education. they have videos and pages and pages of information regarding thread, kinds, weights and property....it is a real eye opening experience.
I personally really like their thread, and and slowly buying a spool here and a spool there....Love their King Tut Quilting thread, which I use on my Older Bernina machine when I quilt. The other thread I like is their "So Fine 50 wt" which is very fine and very strong, that is all that I use anymore for piecing, IMHO the fine thread reduces the bulk of the seams......and that is my two cents on the subject ....