Janome's can be picky (but I still love mine). However, put the thread on the upright spindle, not the parallel one that is usually used. Yes, it can make a difference because of the way the thread comes off.

I use Thread Art thread. I love their thread. I have never had a problem with it-so far.

i use coats and clark and my kenmore has no problem with it, i am now trying out supior threads bottom line and sew fine , they do have charts to help with using the correct thread and some fantastic videos to watch about thread,i also use organ titanium needles for everything and i love them

When I'm having fits, I switch to a bigger needle. I find that when using a smaller needle causes the thread to break and by switching to a larger needle it makes a bigger hole and my problems go away.

My vintage machine isn't the least bit fussy, but I like Isacord. Color is more important to me, so it's whatever I have in the right color.

My Janome 4800 would only take synthetic threads for FMQ. I successfully used Janome or Robison Anton embroidery threads (recommended to me by customer services at Janome UK). I wanted to use King Tut, but it always jammed in the top of the machine. I bought a Janome 7700 at the beginning of this year, and am still getting to know it. So far I've used Superior Rainbows and So Fine very successfully. I've just done a project for the Leah Day Quilt Along using Bottom Line top and bottom, because it was the only thread I had in the colour I wanted to use. At first it shredded and broke a few times, but that stopped when I used a Schmetz top stitch needle and sewed a bit more slowly. I was very pleased with the results. I've not yet tried King Tut, apart from when I was test-driving the dealer's 7700 - it worked then, so I'm really hoping it'll be OK in mine.

I have the Janome 7700 and it's no to fussy. It's a great machine.

Connecting Threads threads, Star thread from C&C (particularly the variegated), and Madeira. Fortunately, my machine is not picky at all. The only thread she does not like is regular C&C.

I use a cheapy Brother mechanical and for FMQ it has never balked at Coats and Clark. It is the most nonfussy machine I've encountered and I do have 5 vintage machines, 4 of them singers.

I noticed this on my MC6500 as well. I have tried Aurifil and it seemed to handle well and the Sulky was bad. I am going to try Bottom Line and Mettler soon. I just purchased both of them recently. I did switch to a 90/14 needle the other day because I was having trouble with my thread "bunching up" randomly on the fabric.