I've FMQ on several different machines- and I have one that simply will not do it nicely - broken or missed stitches. And it happens to be my main sewing machine too, so I was ready to give up.
But then I tried it using my old Singer 15 with a hopping foot- and I can do almost anything with it. I've tried several others, but so far I've not found one that does better than the Singer 15 (and I've done it with three different 15's with good results on all of them).
I use it for smaller projects and embellishments that I don't want to do with the long arm.