I used to use Floriani thread, and found it broke on any machine I used.  I was advised to use Isacord, and I haven't had any more problems.  Some people have no problem with Floriani, but I gave all mine away.  I bought it at a sewing and quilt expo when polyester thread was just becoming popular.  Not one to do things in a small way, I bought a big box of it!  Guess it's like anything else; sometimes we have to experiment a little to find what works best for our machines.  Sue