Disclaimer: I have not received any monies or free product from Superior Threads. This is my honest and unbiased opinion, no one from Superior Threads has contacted me for my opinion.
From left to right:
Superior So Fine is a polyester 5owt, 3 ply thread, a 3,280 yard spool is US$16.90
Aurifil 50wt, 2 ply thread, 1,420 yards is US$11.99
Superior Kimono Silk #100 thread 1,090 yards was US$12.60 on sale at Superior Threads, regularily US$17.00
Mettler 50wt thread, 547 yard spool – can’t remember how much I paid.
I love Superior thread, especially their Kimono Silk Thread, it’s thin, stronger than cotton and a natural fibre. I love it more than Aurifil 50wt cotton and the biggest differences are a) NO lint and b) extremely flat seams. I plan to use it on my next project from start to finish. The Superior So Fine is a 50wt 3 ply thread which appears to be marginally thinner than the Aurifil 50wt 2 ply cotton. The Mettler appears to be the thickest 50wt thread and approximately the same as Gutermann, in my personal opinion. After using Kimono Silk, Gutermann and Mettler feels like sewing with rope.
I’d love to hear about your experience with different threads.