i've used all sorts of threads since i began this adventure called Quilting. at first i used the general purpose poly-cotton blends because they are the least expensive. then i discovered websites like threadart.com and connectingthreads.com.
the prices there are very competitive with a certain bigbox store we all love to hate. when i switched to cotton thread i discovered three things:
(1) it's easier to pick/pull/rip out the stitches when i use cotton thread. that's an especially important benefit to me because i do sooooooo much reverse sewing.
(2) cotton thread is more likely to "become part of the quilt" when i use it to do machine quilting. polyester tends to just sit on top.
(3) cotton thread is easier to use when i hand-quilt. i get fewer knots, for one thing.
a very kind person gave me several spools of some VERY expensive cotton thread. like $9 and $12 per spool! i was suitably grateful and will remember and lover her forever as an extremely generous soul. but i've found that thread from threadart (TA) and connecting threads (CT) work just as well. lately i've been buying all my thread from CT. their solid cottons are a even tha nicer than TA and only a little bit more 'spensive. others may disagree, but i think my CT threads perform better than the ones i used with the killer pricetags.
i used to try to match the color of my thread to the colors in the fabrics while piecing. i gave that up when i discovered that:
(1) it almost never matters if the thread and fabrics match during piecing. i've pieced using white fabs and black thread and you can't tell the difference.
(2) by switching to neutrals i save tons of money because i can buy the big cones.
(3) when there's some contrast between the colors of the threads and fabrics, it's easier to see the stitches if i need to pick them out. (are you detecting a trend here? :lol: )
the best thing you can do for yourself is to shop around. buy one or two spools of each thread you find that fits into your budget. experiment until you find the one you like best.
then ignore everybody who thinks you made the wrong selection. ;-)