I normally use the closest of what I have (several brands) to kind of match what is being called for. I love the organizer that comes with Viking machines because I can go into the thread manager and enter all of my threads, brand and color and then I can tell my software to pick colors out of all of what is entered that is close to what is being called for. Sometimes it's all one color and other times its a really big mix but it works great. I also use the thread manager as a guide when I go to the store because I can print it out and have a list of what I have. I use RA (you can order it from Sears on line for 3.99, great price) Floriani, Sulky, Jenny Haskins, Prencia, and a few others that I can't remember right now. My machine likes it all and it should for what I paid for it; no finichky machines for me.