I've only used sulky and I haven't done much machine embroidery. I've also used the metallics..... and I will say from my experience, the metallics are a challenge. I have also used silk thread for embroidery and like it the most for the things I have done. I agree with ckcwl and ka9sdn, get a couple different spools and try them out. Wait for that huge investment until you know what YOU want.