If you compare the yardage on a spool of Coats and Clark you may find you are spending much more then a spool of the better cotton thread. Coats is made by spinning together lengths of thread pieces from short staple cotton, the cheapest cotton. Look closely at C&C and you will see slubs especially where the ends join. That can cause all matter of tension and stitching problems. Long staple Egyptian cotton is the best and the best manufactured is all one length like Aurifil (Mako) and Superior Masterpiece. There is a legit reason why some thread cost more then others to manufacture for quality. C&C cotton works great in the older vintage machines as that was how thread was made then. Not so much the best for the newer inside threading machines that most have auto tension and other settings.

Thread! Yikes, through the years I feel I have been told a lot of stories about thread. I even had an instructor tell us if we are sewing on cotton, we must use cotton thread, poly thread on poly fabric, etc. I think that's all baloney. I used Coats and Clarks for years and had no problems. I only shied away from it when I was "informed" that the thread was inferior. I would stay away from cheaply priced thread that is thrown into a bin at a store. None of my machines are fussy about what thread I use so I have a hard time getting behind purchasing expensive thread especially when the less expensive brands have stood the test of time. My girlfriend uses the large cones of Coats and Clarks for her free motion work and she swears by that brand. So once again, it's an issue that will continue to be visited again and again.

"Don't kill me...it's a real question". :D That cracked me up.

Some of the big bloggers, yes, are being sponsored , so you are right in assuming an apparent bias. That being said,
I have bought Aurifil and preferred it over CT or C&C, but for the price it's not my go-to piecing thread. CT thread is
what my daughter bought me in 12 colors of the rainbow, so I use it for piecing and probably will "till the cows come home" since it's there. :) It's a bit lintier, but I enjoy cleaning out lint (I know I'm weird--I enjoy cleaning out the lint trap every load from the dryer, too, and using a lint roller on clothes.)

I'd say if it's working for you, why change? But do give yourself permission to try a spool of Aurifil, Superior, or Glide and see if it makes a noticeable enough difference for you to spend more. Go medium grey so you get the versatility of piecing and quilting most things without worrying about color clashing.

Average non sale prices:

C&C Dual Duty 250 yard $5.25 cheap short staple cotton pieces spun into one long length
Aurifil 220 yard spool is $5.25 Egyptian long staple cotton, smooth all one length.

Going to be honest and say I buy on sale and I don’t mind cleaning the lint! I have a fairly large bag of Coats and Clark in a rainbow of colors that I bought years ago and hated to waste so when I bought my new machine I asked.....and was told if it worked well not to worry. It’s fine. I like the basic colors that are 2.99 for a large spool for my piecing.

coats and clark have stood the test of time for thread

When I bought my latest machine, it came with “classes.” I learned a bit, but to me it seemed like little more than a sales pitch. “Don’t use thread, needles, bobbins, fabric from anywhere but our store. If you do, it will ruin your machine.” Personally, I use whatever I like. I use lots of C&C and connecting threads. Lots of people love the high dollar threads. To each their own. Use what you like and don’t stress about what anyone else uses.

For sewing my blocks together, I use Connecting Threads Essentials thread, for my FMQ I use Metro Machine Embroidery thread. Both companies have excellent customer service and prices.

Use the thread that works for you and your machine. That is all that counts.

Me, I have brands I prefer, only because I have consistently had good results with them and I do not want to mess with a good thing.

I have used Aurifil for EPP and was very happy with the results. It slides through the fabric like butter.

I use C&C and have for many years. I also in the last 10 or so years use Connecting Threads,

They work for me.