I have different machines too, some old, some just older and some newer. All my none computer machines I could use anything in and they sewed like little champs (I learned on C & C). But my machines with "MOTHER BOARDS" are a totally different story. When a machine has a mother board in it, it's just like turning your computer into a sewing machine. Lint (from thread or fabric), can kill a mother board. And just like a computer the mother board is spendy to replace, but unlike a computer that you can work with other mother boards. Sewing machines can ONLY use the mother boards they come with (or one JUST LIKE IT). If a machine is only a couple of years old you should be able to get a new mother board without any problems. But if you have an older machine, your not so lucky. That's part of the problem after price. I know for my Pfaff, when Pfaff moved to Japan - that was the end of my mother board. My machine is older, but works like a dream. Because of no available mother board, each time I take her into the shop I"m asked if I would like to sell her". My sewing people know I have other machines, so it's not that they are trying to sell me a new one. It's just that they are looking for parts to keep them going, my Pfaff is almost 20 years old and I have been offered $1,000.00 for her (NO SALE). C & C used to put off a LOT of lint, not so much now. But I'm not able to take the chance with it. As for WEAK thread, any time ANY thread is made in Mexico you will have problems. It doesn't matter what kind - I use Gutterman and a few years ago, it was on a great sale all over town - it was because it was made in Mexico and it was weak and causing problems. So now I always look at my thread, I still use C & C for things, but not in my computerized machines.