I only use threads from Superior Threads. Their website has an amazing amount of user information and help on it, and they have real sample cards for all threads they sell. It is just a bit more expensive, but the performance is so much better than any other brand, it's worth it to me. While I've used other brands and they turn out ok, this brand seems to be the best for me. I've used it my home machines as well as my mid-arm, also in my bobbins, with very few issues. Many cone/spool sizes, and hundreds of colors, fibers, sizes. They also run sales that help bring the price down a bit. They have a sample pack you can get to experiment with, and single spools are sold in a lot of quilt shops. Might be a good place to start.