I love Guterman thread, but my Janome 6600 doesn't like it at all, and I have a nice size stash of it. So, I switched to Aurifil and she purrs away with it. I can use my Guterman in my Featherweights though, and they're all just fine with it. Whew! What a relief because I bought a ton of Gutermann!
Watch for Hancock's and JoAnn's to run the Guterman on sale. Wish I could find a store going out of business with thread that cheap! What a great bargain.